3.41% is the change from 615 to 636
Calculation steps:
[( 636 - 615 ) ÷ 615] x 100 = 3.41%
Formula
Percentage change = [(636 - 615) / 615] x 100
Subtract the new number by the original number
636 - 615 = 21
21 ÷ 615 = 0.03414634146341464
0.03414634146341464 x 100 = 3.41%