-47.3% is the change from 315 to 166
Calculation steps:
[( 166 - 315 ) ÷ 315] x 100 = -47.3%
Formula
Percentage change = [(166 - 315) / 315] x 100
Subtract the new number by the original number
166 - 315 = -149
-149 ÷ 315 = -0.473015873015873
-0.473015873015873 x 100 = -47.3%