Question 4 [25 marks]

(a) Consider the following financial data (in millions of dollars) for Costello Laboratories over the period of 20142018:

year	sales	net income	total assets	common equity
2014	$3,800	$500	$3,900	$1,800
2015	4,400	650	4,400	2,100
2016	5,000	750	4,800	2,500
2017	5,400	860	4,900	2,700
2018	6,200	1,000	5,600	2,800

Calculate Costellos return on equity for each year. (5 marks)