-50% is the change from 316 to 158
Calculation steps:
[( 158 - 316 ) ÷ 316] x 100 = -50%
Formula
Percentage change = [(158 - 316) / 316] x 100
Subtract the new number by the original number
158 - 316 = -158
-158 ÷ 316 = -0.5
-0.5 x 100 = -50%
Example