-50.15% is the change from 331 to 165
Calculation steps:
[( 165 - 331 ) ÷ 331] x 100 = -50.15%
Formula
Percentage change = [(165 - 331) / 331] x 100
Subtract the new number by the original number
165 - 331 = -166
-166 ÷ 331 = -0.5015105740181269
-0.5015105740181269 x 100 = -50.15%