-97.66% is the change from 171 to 4
Calculation steps:
[( 4 - 171 ) ÷ 171] x 100 = -97.66%
Formula
Percentage change = [(4 - 171) / 171] x 100
Subtract the new number by the original number
4 - 171 = -167
-167 ÷ 171 = -0.9766081871345029
-0.9766081871345029 x 100 = -97.66%