-8.91% is the change from 550 to 501
Calculation steps:
[( 501 - 550 ) ÷ 550] x 100 = -8.91%
Formula
Percentage change = [(501 - 550) / 550] x 100
Subtract the new number by the original number
501 - 550 = -49
-49 ÷ 550 = -0.0890909090909091
-0.0890909090909091 x 100 = -8.91%