The following data has been collected about Keller Company's stockholders' equity accounts:

Common stock $10 par value 20,000 shares authorized, 10,000 shares issued, and 9,000 shares outstanding

$ 100,000

Paid-in capital in excess of par value, common stock

50,000

Retained earnings

25,000

Treasury stock

11,500

Assuming the treasury shares were all purchased at the same price, the number of shares of treasury stock is