On January 1, 2011, Tuscany Corporation purchased 1,000 shares of treasury stock. Other information regarding Tuscany Corporation is provided below.

2010

2011

Net income

$200,000

$210,000

Dividends on preferred stock

$ 30,000

$ 30,000

Dividends on common stock

$ 20,000

$ 25,000

Weighted average number of common shares outstanding

10,000

9,000

Common stockholders’ equity beginning of year

$600,000

$750,000

Common stockholders’ equity end of year

$750,000

$830,000

Compute (a) return on common stockholders’ equity for each year and (b) discuss the changes.