-15% is the change from 220 to 187
Calculation steps:
[( 187 - 220 ) ÷ 220] x 100 = -15%
Formula
Percentage change = [(187 - 220) / 220] x 100
Subtract the new number by the original number
187 - 220 = -33
-33 ÷ 220 = -0.15
-0.15 x 100 = -15%
Example