800% is the change from 15 to 135
Calculation steps:
[( 135 - 15 ) ÷ 15] x 100 = 800%
Formula
Percentage change = [(135 - 15) / 15] x 100
Subtract the new number by the original number
135 - 15 = 120
120 ÷ 15 = 8
8 x 100 = 800%
Example