-0.91% is the change from 550 to 545
Calculation steps:
[( 545 - 550 ) ÷ 550] x 100 = -0.91%
Formula
Percentage change = [(545 - 550) / 550] x 100
Subtract the new number by the original number
545 - 550 = -5
-5 ÷ 550 = -0.00909090909090909
-0.00909090909090909 x 100 = -0.91%