2.45% is the change from 815 to 835
Calculation steps:
[( 835 - 815 ) ÷ 815] x 100 = 2.45%
Formula
Percentage change = [(835 - 815) / 815] x 100
Subtract the new number by the original number
835 - 815 = 20
20 ÷ 815 = 0.024539877300613498
0.024539877300613498 x 100 = 2.45%