	As of December 31, 2019			As of December 31, 2018
Revolving credit facility(A)	$	—		$	28,059
Term loan		200,000			200,000
Australian term loan facility(B)		842,520			—
4.000% Senior Unsecured Notes due 2022(B)		560,650			573,350
2.550% Senior Unsecured Notes due 2023(B)		530,280			—
5.500% Senior Unsecured Notes due 2024		300,000			300,000
6.375% Senior Unsecured Notes due 2024		500,000			500,000
3.325% Senior Unsecured Notes due 2025(B)		560,650			573,350
5.250% Senior Unsecured Notes due 2026		500,000			500,000
5.000% Senior Unsecured Notes due 2027		1,400,000			1,400,000
3.692% Senior Unsecured Notes due 2028(B)		795,420			—
4.625% Senior Unsecured Notes due 2029		900,000			—
	$	7,089,520		$	4,074,759
Debt issue costs and discount, net		(65,841	)		(37,370	)
	$	7,023,679		$	4,037,389

As of December 31, 2019, principal payments due on our debt (which exclude the effects of any discounts, premiums, or debt issue costs recorded) are as follows ($ amounts in thousands):

2020	$	—
2021		—
2022		760,650
2023		530,280
2024		1,642,520
Thereafter		4,156,070
Total	$	7,089,520

On February 1, 2017, we replaced our previous unsecured credit facility with a new revolving credit and term loan agreement. The new agreement included a $1.3 billion unsecured revolving loan facility, a $200 million unsecured term loan facility, and a new €200 million unsecured term loan facility. The unsecured revolving loan facility matures in February 2021 and can be extended for an additional 12 months at our option. The $200 million unsecured term loan facility matures on February 1, 2022, and the €200 million unsecured term loan facility had a maturity date of January 31, 2020; however, it was paid off on March 30, 2017 — see below. The term loan and/or revolving loan commitments may be increased in an aggregate amount not to exceed $500 million.

At our election, loans under the Credit Facility may be made as either ABR Loans or Eurodollar Loans. The applicable margin for term loans that are ABR Loans is adjustable on a sliding scale from 0.00% to 0.95% based on our current credit rating. The applicable margin for term loans that are Eurodollar Loans is adjustable on a sliding scale from 0.90% to 1.95% based on our current credit rating. The applicable margin for revolving loans that are ABR Loans is adjustable on a sliding scale from 0.00% to 0.65% based on our current credit rating. The applicable margin for revolving loans that are Eurodollar Loans is adjustable on a sliding scale from 0.875% to 1.65% based on our current credit rating. The commitment fee is adjustable on a sliding scale from 0.125% to 0.30% based on our current credit rating and is payable on the revolving loan facility.

At December 31, 2019 and 2018, we had $0 and $28.1 million, respectively, outstanding on the revolving credit facility. At December 31, 2019, our availability under our revolving credit facility was $1.3 billion. The weighted-average interest rate on this facility was 2.0% and 2.7% during 2019 and 2018, respectively.

At December 31, 2019 and 2018, the interest rate in effect on our term loan was 3.30% and 3.89%, respectively.

On May 23, 2019, we entered into an AUD $1.2 billion term loan facility agreement with Bank of America, N.A., as administrative agent, and several lenders from time-to-time are parties thereto. The term loan facility matures on May 23, 2024. The interest rate under the term loan is adjustable based on a pricing grid from 0.85% to 1.65%, dependent on our current senior unsecured credit rating. On June 27, 2019, we entered into an interest rate swap transaction (effective July 3, 2019) to fix the interest rate to approximately 1.20% for the duration of the loan. The current applicable margin for the pricing grid (which can vary based on the Company’s credit rating) is 1.25% for an all-in fixed rate of 2.45%.

On August 19, 2015, we completed a €500 million senior unsecured notes offering (“4.000% Senior Unsecured Notes due 2022”). Interest on the notes is payable annually on August 19 of each year. The notes pay interest in cash at a rate of 4.000% per year. The notes mature on August 19, 2022. We may redeem some or all of the 4.000% Senior Unsecured Notes due 2022 at any time. If the notes are redeemed prior to 90 days before maturity, the redemption price will be 100% of their principal amount, plus a make-whole premium, plus accrued and unpaid interest to, but excluding, the applicable redemption date. Within the period beginning on or after 90 days before maturity, the notes may be redeemed, in whole or in part, at a redemption price equal to 100% of their principal amount, plus accrued and unpaid interest to, but excluding, the applicable redemption date. The 4.000% Senior Unsecured Notes due 2022 are fully and unconditionally guaranteed on an unsecured basis by us. In the event of a change of control, each holder of the notes may require us to repurchase some or all of our notes at a repurchase price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest to the date of the purchase.

On December 5, 2019, we completed a £400 million senior unsecured notes offering (“2.550% Senior Unsecured Notes due 2023”). Interest on the notes is payable annually on December 5 of each year. The notes pay interest in cash at a rate of 2.550% per year. The notes mature on December 5, 2023. We may redeem some or all of the 2.550% Senior Unsecured Notes due 2023 at any time. If the notes are redeemed prior to 30 days before maturity, the redemption price will be equal to 100% of the principal amount, plus a make-whole premium, plus accrued and unpaid interest to, but excluding, the applicable redemption date. The 2.550% Senior Unsecured Notes due 2023 are fully and unconditionally guaranteed on an unsecured basis by us. In the event of change of control, each holder of the notes may require us to repurchase some or all of our notes at a repurchase price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest to the date of the purchase.

On April 17, 2014, we completed a $300 million senior unsecured notes offering (“5.500% Senior Unsecured Notes due 2024”). Interest on the notes is payable semi-annually on May 1 and November 1 of each year. The notes pay interest in cash at a rate of 5.500% per year. The notes mature on May 1, 2024. We may redeem some or all of the notes at any time prior to May 1, 2019 at a “make-whole” redemption price. On or after May 1, 2019, we may redeem some or all of the notes at a premium that will decrease over time. In the event of a change of control, each holder of the notes may require us to repurchase some or all of our notes at a repurchase price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest to the date of purchase.

On February 22, 2016, we completed a $500 million senior unsecured notes offering (“6.375% Senior Unsecured Notes due 2024”). Interest on the notes is payable on March 1 and September 1 of each year. Interest on the notes is paid in cash at a rate of 6.375% per year. The notes mature on March 1, 2024. We may redeem some or all of the notes at any time prior to March 1, 2019 at a “make whole” redemption price. On or after March 1, 2019, we may redeem some or all of the notes at a premium that will decrease over time. In addition, at any time prior to March 1, 2019, we may redeem up to 35% of the notes at a redemption price equal to 106.375% of the aggregate principal amount thereof, plus accrued and unpaid interest thereon, using proceeds from one or more equity offerings. In the event of a change in control, each holder of the notes may require us to repurchase some or all of the notes at a repurchase price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest to the date of purchase.

their principal amount, plus accrued and unpaid interest to, but excluding, the applicable redemption date. The 3.325% Senior Unsecured Notes due 2025 are fully and unconditionally guaranteed on a senior unsecured basis by us. In the event of a change of control, each holder of the notes may require us to repurchase some or all of our notes at a repurchase price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest up to, but excluding, the date of the purchase.

On July 22, 2016, we completed a $500 million senior unsecured notes offering (“5.250% Senior Unsecured Notes due 2026”). Interest on the notes is payable on February 1 and August 1 of each year. Interest on the notes is to be paid in cash at a rate of 5.250% per year. The notes mature on August 1, 2026. We may redeem some or all of the notes at any time prior to August 1, 2021 at a “make whole” redemption price. On or after August 1, 2021, we may redeem some or all of the notes at a premium that will decrease over time. In addition, at any time prior to August 1, 2019, we may redeem up to 35% of the notes at a redemption price equal to 105.250% of the aggregate principal amount thereof, plus accrued and unpaid interest thereon, using proceeds from one or more equity offerings. In the event of a change in control, each holder of the notes may require us to repurchase some or all of the notes at a repurchase price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest to the date of purchase.

On September 7, 2017, we completed a $1.4 billion senior unsecured notes offering (“5.000% Senior Unsecured Notes due 2027”). Interest on the notes is payable on April 15 and October 15 of each year. The notes pay interest in cash at a rate of 5.000% per year. The notes mature on October 15, 2027. We may redeem some or all of the notes at any time prior to October 15, 2022 at a “make whole” redemption price. On or after October 15, 2022, we may redeem some or all of the notes at a premium that will decrease over time. In addition, at any time prior to October 15, 2020, we may redeem up to 40% of the notes at a redemption price equal to 105% of the aggregate principal amount thereof, plus accrued and unpaid interest thereon, using proceeds from one or more equity offerings. In the event of a change in control, each holder of the notes may require us to repurchase some or all of the notes at a repurchase price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest to the date of purchase.

On December 5, 2019, we completed a £600 million senior unsecured notes offering (“3.692% Senior Unsecured Notes due 2028”). The notes were issued at 99.998% of par value. Interest on the notes is payable on June 5 of each year. The notes pay interest in cash at a rate of 3.692% per year. The notes mature on June 5, 2028. We may redeem some or all of the 3.692% Senior Unsecured Notes due 2028 at any time. If the notes are redeemed prior to 30 days before maturity, the redemption price will be equal to 100% of the principal amount, plus a make-whole premium, plus accrued and unpaid interest to, but excluding, the applicable redemption date. The 3.692% Senior Unsecured Notes due 2028 are fully and unconditionally guaranteed on an unsecured basis by us. In the event of change of control, each holder of the notes may require us to repurchase some or all of our notes at a repurchase price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest to the date of the purchase.

On July 26, 2019, we completed a $900 million senior unsecured notes offering (“4.625% Senior Unsecured Notes due 2029”). Interest on the notes is payable on February 1 and August 1 of each year, commencing on February 1, 2020. The notes were issued at 99.5% of par value, pay interest at a rate of 4.625% per year and mature on August 1, 2029. We may redeem some or all of the notes at any time prior to August 1, 2024 at a “make whole” redemption price. On or after August 1, 2024, we may redeem some or all of the notes at a premium that will decrease over time. In addition, at any time prior to August 1, 2022, we may redeem up to 40% of the notes at a redemption price equal to 104.625% of the aggregate principal amount thereof, plus accrued and unpaid interest thereon, using proceeds from one or more equity offerings. In the event of a change in control, each holder of the notes may require us to repurchase some or all of the notes at a repurchase price equal to 101% of the aggregate principal amount of the notes plus accrued and unpaid interest to the date of purchase.

In preparation of the joint venture with Primotop described under “2018 Activity” in Note 3, we issued secured debt on August 3, 2018, resulting in gross proceeds of €655 million. Provisions of the secured debt included a term of seven years and a swapped fixed rate of approximately 2.3%. Subsequently, on August 31, 2018, the secured debt was contributed along with the related real estate of 71 properties to form the joint venture.

On July 10, 2019, we received a commitment to provide a senior unsecured bridge loan facility to fund our investment in Prospect. With this commitment, we paid $4.2 million of underwriting and other fees. However, this commitment was cancelled with the completion of the debt and equity offerings in July 2019, which resulted in fully expensing the total amount of underwriting and other fees that were paid.

In anticipation of funding our Australian acquisition in June 2019 and the Circle Health Ltd. (“Circle”) transaction in January 2020, we entered into term loans on the date these deals were signed that had a delayed draw feature. This feature allowed for us to not draw on the term loans until needed to fund these transactions. However, with this type of structure, we incurred approximately $2.0 million in accelerated debt issue cost amortization expense during 2019.

With the replacement of our previous credit facility, the early redemption of senior unsecured notes, the payoff of our €200 million term loan, the cancellation of a $1.0 billion term loan facility commitment, and the pre-payment of a $12.9 million mortgage loan, we incurred a charge of $32.6 million (including redemption premiums and accelerated amortization of deferred debt issuance cost and commitment fees) during the year ended December 31, 2017.

Our debt facilities impose certain restrictions on us, including restrictions on our ability to: incur debts; create or incur liens; provide guarantees in respect of obligations of any other entity; make redemptions and repurchases of our capital stock; prepay, redeem, or repurchase debt; engage in mergers or consolidations; enter into affiliated transactions; dispose of real estate or other assets; and change our business. In addition, the credit agreements governing our Credit Facility limit the amount of dividends we can pay as a percentage of normalized adjusted funds from operations (“NAFFO”), as defined in the agreements, on a rolling four quarter basis. Through 2019, the dividend restriction was 95% of NAFFO. The indentures governing our senior unsecured notes also limit the amount of dividends we can pay based on the sum of 95% of NAFFO, proceeds of equity issuances and certain other net cash proceeds. Finally, our senior unsecured notes require us to maintain total unencumbered assets (as defined in the related indenture) of not less than 150% of our unsecured indebtedness.

In addition to these restrictions, the Credit Facility contains customary financial and operating covenants, including covenants relating to our total leverage ratio, fixed charge coverage ratio, secured leverage ratio, consolidated adjusted net worth, unsecured leverage ratio, and unsecured interest coverage ratio. The Credit Facility also contains customary events of default, including among others, nonpayment of principal or interest, material inaccuracy of representations, and failure to comply with our covenants. If an event of default occurs and is continuing under the Credit Facility, the entire outstanding balance may become immediately due and payable. At December 31, 2019, we were in compliance with all such financial and operating covenants.