Comparing income statements on an annual basis is one part of the trend analysis. However, simply noting, for example, that sales are higher by $1 million this year is insufficient when identifying trends. Instead, track the sales growth rate over the last few years to identify a trend. Calculate the percentage change by dividing this year's sales by last year's sales and subtracting 1. For example, if sales this year were $127 million and last year's sales were $114 million, the sales growth rate was 11.4 percent. Repeat for other years and chart the results to visualize the trend. Use the same formula to calculate the percentage change for other income statement items.