I need the answer to this

Vertical analysis (common-size) percentages for Vallejo Company’s sales, cost of goods sold, and expenses are listed here.

Vertical Analysis		2012		2011		2010
Sales		100	%		100	%		100	%
Cost of goods sold		60.3			63.7			65.2
Expenses		25.4			27.2			28.1

Did Vallejo’s net income as a percent of sales increase, decrease, or remain unchanged over the 3-year period? Provide numerical support for your answer.