Connors, Inc. provides the following information for 2017:
Net income $180,000
Market price per share of common stock $20.00/share
Common stockholders' equity at Jan. 1, 2017 $1,100,000
Common stockholders' equity at Dec. 31, 2017 $1,500,000
12% preferred stock outstanding $100,000
Calculate return on common stockholders' equity.