-9.09% is the change from 55 to 50
Calculation steps:
[( 50 - 55 ) ÷ 55] x 100 = -9.09%
Formula
Percentage change = [(50 - 55) / 55] x 100
Subtract the new number by the original number
50 - 55 = -5
-5 ÷ 55 = -0.09090909090909091
-0.09090909090909091 x 100 = -9.09%