Vertical analysis (common size) percentages

Vertical analysis (common size) percentages

Vertical analysis (common size) percentages for Kochheim Company”s sales revenue, cost of goods sold, and expenses are shown below.
Vertical Analysis
2015
2014
2013
Sales revenue
100.0
100.0
100.0
Cost of goods sold
60.2
62.4
63.5
Expenses
25.0
25.6
27.5
Did Kochheim”s net income as a percentage of sales increase, decrease, or remain unchanged over the 3-year period? Provide numerical support for your answer.