-18.18% is the change from 220 to 180
Calculation steps:
[( 180 - 220 ) ÷ 220] x 100 = -18.18%
Formula
Percentage change = [(180 - 220) / 220] x 100
Subtract the new number by the original number
180 - 220 = -40
-40 ÷ 220 = -0.18181818181818182
-0.18181818181818182 x 100 = -18.18%