-90.48% is the change from 315 to 30
Calculation steps:
[( 30 - 315 ) ÷ 315] x 100 = -90.48%
Formula
Percentage change = [(30 - 315) / 315] x 100
Subtract the new number by the original number
30 - 315 = -285
-285 ÷ 315 = -0.9047619047619048
-0.9047619047619048 x 100 = -90.48%