-23.45% is the change from 550 to 421
Calculation steps:
[( 421 - 550 ) ÷ 550] x 100 = -23.45%
Formula
Percentage change = [(421 - 550) / 550] x 100
Subtract the new number by the original number
421 - 550 = -129
-129 ÷ 550 = -0.23454545454545456
-0.23454545454545456 x 100 = -23.45%