The balance sheets at the end of each of the first two years of operations indicate the following:
Year 2 Year 1
Total current assets $600,000 $560,000
Total investments 60,000 40,000
Total property, plant, and equipment 900,000 700,000
Total current liabilities 125,000 65,000
Total long-term liabilities 350,000 250,000
Preferred 9% stock, $100 par 100,000 100,000
Common stock, $10 par 600,000 600,000
Paid­in capital in excess of par-Common stock 75,000 75,000
Retained earnings 310,000 210,000

If net income is $150,000 and interest expense is $20,000 for Year 2, what is the rate earned on stockholders' equity for Year 2?