-87.3% is the change from 315 to 40
Calculation steps:
[( 40 - 315 ) ÷ 315] x 100 = -87.3%
Formula
Percentage change = [(40 - 315) / 315] x 100
Subtract the new number by the original number
40 - 315 = -275
-275 ÷ 315 = -0.873015873015873
-0.873015873015873 x 100 = -87.3%