-50% is the change from 422 to 211
Calculation steps:
[( 211 - 422 ) ÷ 422] x 100 = -50%
Formula
Percentage change = [(211 - 422) / 422] x 100
Subtract the new number by the original number
211 - 422 = -211
-211 ÷ 422 = -0.5
-0.5 x 100 = -50%
Example