-11.95% is the change from 251 to 221
Calculation steps:
[( 221 - 251 ) ÷ 251] x 100 = -11.95%
Formula
Percentage change = [(221 - 251) / 251] x 100
Subtract the new number by the original number
221 - 251 = -30
-30 ÷ 251 = -0.11952191235059761
-0.11952191235059761 x 100 = -11.95%