Walgreen CEO Gregory D. Wasson’s total compensation slipped in fiscal 2012, as earnings sank 21 percent and a contract dispute hurt revenue for the nation’s largest drugstore operator.

Wasson, 54, received compensation valued at about $12 million for the fiscal year that ended Aug. 31, according to the Deerfield, Ill., company’s annual proxy statement filed Monday. That represented a 1 percent drop compared to fiscal 2011.