10. Go to the Sales by Service worksheet, which contains a PivotTable named ServicePivot that compares the Quarter 1, Quarter 4, and Annual sales for each service provided in 2021. Nadia wants to know the difference and the percentage of difference between the Quarter 4 and Quarter 1 sales and display the average total sales for each service. Insert a calculated field named Difference that subtracts the Qtr1 field amount from the Qtr4 field amount. In cell E2, use +/- Q4 to Q1 as the column label. 11. Insert another calculated field named % Difference that subtracts the Qtr 1 field amounts from the Qtr 4 field amounts, and then divides the result by the Qtr 1 field amount. In cell F2, use % Q4 to Q1 as the column label. Change the number format of the % Q4 to Q1 amounts to Percentage with 2 decimal points.