Common Stock and Other Equity Related Transactions

On October 26, 2018, we entered into our current at-the-market ("ATM") equity offering program with certain sales agents, pursuant to which we may sell, from time-to-time, shares of our Common Stock with a par value of $0.01 per share, up to an aggregate offering price of up to $200.0 million. The full capacity remained available for issuance as of December 31, 2018.

The following table presents the shares that were issued under our prior ATM equity offering program:



	Years Ended December 31,
(amounts in thousands, except share data)	2018		2017		2016
Shares of Common Stock sold	861,141		1,380,017		683,548
Weighted average price	$	91.45	$	87.46	$	73.15
Total gross proceeds	$	78,755	$	120,698	$	50,000
Commissions paid to sales agents	$	1,028	$	1,512	$	657

On May 10, 2016, we amended and restated the 1997 Non-Qualified Employee Stock Purchase Plan ("ESPP"). Pursuant to the ESPP, certain of our employees and directors may each annually acquire up to $250,000 of our common stock. The aggregate number of shares of common stock available under the ESPP shall not exceed 2,000,000, subject to adjustment by our Board of Directors. The common stock may be purchased monthly at a price equal to 85% of the lesser of: (a) the closing price for a share of common stock on the last day of the offering period; and (b) the closing price for a share of common stock on the first day of the offering period. Shares of common stock issued through the ESPP for the years ended December 31, 2018, 2017 and 2016 were 22,071, 24,715 and 17,037, respectively.

The following table presents the changes in our outstanding common stock (excluding OP Units of 5,745,966, 5,834,100, and 7,170,000 outstanding at December 31, 2018, 2017 and 2016, respectively):



	Years Ended December 31,
	2018		2017		2016
Shares outstanding at January 1,	88,585,160		85,529,386		84,253,065
Common stock issued through the ATM Equity Offering Program	861,141		1,380,017		683,548
Common stock issued through conversion of OP Units	88,134		1,335,900		37,678
Common stock issued through exercise of options	202,800		220,000		440,000
Common stock issued through restricted stock grants	192,505		130,426		133,717
Common stock forfeitures	—		(990	)	—
Common stock issued through ESPP and Dividend Reinvestment Plan	22,572		25,101		17,373
Common stock repurchased and retired	(31,294	)	(34,680	)	(35,995	)
Shares outstanding at December 31,	89,921,018		88,585,160		85,529,386

During the years ended December 31, 2018, 2017 and 2016, we repurchased shares of common stock representing common stock surrendered to satisfy income tax withholding obligations primarily due to the vesting of restricted stock grants at a weighted average price of $96.23, $89.02 and $72.22 per share, respectively.

As of December 31, 2018, 2017 and 2016, ELS' percentage ownership of the Operating Partnership was approximately 94.0%, 93.8% and 92.3%, respectively. The remaining approximately 6.0%, 6.2% and 7.7% as of December 31, 2018, 2017 and 2016, respectively, was owned by the Common OP Unitholders.

The following regular quarterly distributions have been declared and paid to common stockholders and common OP Unit non-controlling interests since January 1, 2016:



Distribution Amount Per Share	For the Quarter Ended	Stockholder Record Date	Payment Date
$0.4250	March 31, 2016	March 25, 2016	April 8, 2016
$0.4250	June 30, 2016	June 24, 2016	July 8, 2016
$0.4250	September 30, 2016	September 30, 2016	October 14, 2016
$0.4250	December 31, 2016	December 30, 2016	January 13, 2017
$0.4875	March 31, 2017	March 31, 2017	April 14, 2017
$0.4875	June 30, 2017	June 30, 2017	July 14, 2017
$0.4875	September 30, 2017	September 29, 2017	October 13, 2017
$0.4875	December 31, 2017	December 29, 2017	January 12, 2018
$0.5500	March 31, 2018	March 30, 2018	April 13, 2018
$0.5500	June 30, 2018	June 29, 2018	July 13, 2018
$0.5500	September 30, 2018	September 28, 2018	October 12, 2018
$0.5500	December 31, 2018	December 28, 2018	January 11, 2019