-81.71% is the change from 164 to 30
Calculation steps:
[( 30 - 164 ) ÷ 164] x 100 = -81.71%
Formula
Percentage change = [(30 - 164) / 164] x 100
Subtract the new number by the original number
30 - 164 = -134
-134 ÷ 164 = -0.8170731707317073
-0.8170731707317073 x 100 = -81.71%