20% is the change from 815 to 978
Calculation steps:
[( 978 - 815 ) ÷ 815] x 100 = 20%
Formula
Percentage change = [(978 - 815) / 815] x 100
Subtract the new number by the original number
978 - 815 = 163
163 ÷ 815 = 0.2
0.2 x 100 = 20%
Example