-70% is the change from 330 to 99
Calculation steps:
[( 99 - 330 ) ÷ 330] x 100 = -70%
Formula
Percentage change = [(99 - 330) / 330] x 100
Subtract the new number by the original number
99 - 330 = -231
-231 ÷ 330 = -0.7
-0.7 x 100 = -70%
Example