7. LONG‑TERM DEBT

Long-term debt consists of the following:


	January 31, 2017		January 31, 2016
Senior unsecured notes	$	1,200.0	$	1,200.0
Less unamortized original issue discount and debt issue costs		18.0		20.5
	$	1,182.0	$	1,179.5

In December 2014, in connection with the Spin‑off, the Company issued $1,200.0 aggregate principal amount of 5.875% senior unsecured notes due 2022 (the “5.875% Notes”), in an offering pursuant to the Securities Act of 1933, as amended. The net proceeds from the issuance of the 5.875% Notes were approximately $1,172.1, of which $750.0 was distributed to Former Parent, leaving KLX with net proceeds of approximately $422.1. The 5.875% Notes are senior unsecured debt obligations of the Company. We also entered into a $750.0 secured revolving credit facility dated as of December 16, 2014 and amended May 19, 2015 (the “Revolving Credit Facility”). As of January 31, 2017 and 2016, long‑term debt consisted of $1,200.0 of our 5.875% Notes.

Letters of credit outstanding under the Revolving Credit Facility aggregated $5.5 at January 31, 2017.

The Revolving Credit Facility is tied to a borrowing base formula, has no financial covenants and has $744.5 of availability as of January 31, 2017. The Revolving Credit Facility bears interest at an annual rate equal to the London interbank offered rate (“LIBOR”) plus the applicable margin (as defined), and expires in May 2020. No amounts were outstanding under the Revolving Credit Facility as of January 31, 2017.

Maturities of long‑term debt are as follows:


Year Ending January 31,
2018	$	—
2019		—
2020		—
2021		—
2022		—
Thereafter		1,200.0
Total	$	1,200.0

Interest expense amounted to $75.9, $77.7, $3.3 and $6.3 for the years ended January 31, 2017 and 2016, December 31, 2014 and the one month ended January 31, 2015, respectively.