(11) CAPITAL STOCK

We have authorized capital stock of 485.0 million shares which includes 475.0 million shares of common stock and 10.0 million shares of preferred stock. We currently have no preferred stock issued or outstanding. The following is a schedule of changes in the number of common shares outstanding since the beginning of 2017:

	Three Months Ended March 31, 2018		Year Ended December 31, 2017
Beginning balance		248,129,430		247,144,356
Restricted stock grants		673,791		539,096
Restricted stock units vested		397,774		344,937
Performance stock units issued		20,430		85,461
Treasury shares issued		895		15,580
Ending balance		249,222,320		248,129,430