-40.36% is the change from 166 to 99
Calculation steps:
[( 99 - 166 ) ÷ 166] x 100 = -40.36%
Formula
Percentage change = [(99 - 166) / 166] x 100
Subtract the new number by the original number
99 - 166 = -67
-67 ÷ 166 = -0.4036144578313253
-0.4036144578313253 x 100 = -40.36%