Type “Year” into A1 (the first cell in column A). Type “Amount” into B1. Type “Growth Rate” into C1.

Click column A (the letter above the column) to select it, and then click the Format button on the Home tab. It’ll be near the top-right corner of Excel. Then, click Format Cells on the menu, select Date in the left panel, and then choose a date format in the right panel. Click OK to save your changes. For column B, you’ll want to format the amounts as currency. Click the “B” above column B to select it, click the Format button on the Home tab, and then click Format Cells on the menu. Click Currency in the left panel, select a currency symbol and format on the right, and then click OK. Column C should be formatted as percentages. Click the “C” above column C, and again, click Format, and then Format Cells. Select Percentage in the left panel, choose the number of decimal places in the right panel, and then click OK.

=AVERAGE(C3:C20) (replace C20 with the address of the actual last cell containing a growth percentage in column C).