-31.43% is the change from 315 to 216
Calculation steps:
[( 216 - 315 ) ÷ 315] x 100 = -31.43%
Formula
Percentage change = [(216 - 315) / 315] x 100
Subtract the new number by the original number
216 - 315 = -99
-99 ÷ 315 = -0.3142857142857143
-0.3142857142857143 x 100 = -31.43%