(a) Consider the following financial data (in millions of dollars) for Costello Laboratories over the period of 2014-2018: Year Sales Net income Total assets 2014 2015 2016 2017 2018 $3,800 4,400 5,000 5,400 6,200 $500 650 750 860 1,000 $3,900 4,400 4.800 4,900 5,600 Common equity $1,800 2,100 2,500 2,700 2,800 Calculate Costello's return on equity for each year