-50% is the change from 164 to 82
Calculation steps:
[( 82 - 164 ) ÷ 164] x 100 = -50%
Formula
Percentage change = [(82 - 164) / 164] x 100
Subtract the new number by the original number
82 - 164 = -82
-82 ÷ 164 = -0.5
-0.5 x 100 = -50%
Example