-34.34% is the change from 166 to 109
Calculation steps:
[( 109 - 166 ) ÷ 166] x 100 = -34.34%
Formula
Percentage change = [(109 - 166) / 166] x 100
Subtract the new number by the original number
109 - 166 = -57
-57 ÷ 166 = -0.3433734939759036
-0.3433734939759036 x 100 = -34.34%