-5.45% is the change from 550 to 520
Calculation steps:
[( 520 - 550 ) ÷ 550] x 100 = -5.45%
Formula
Percentage change = [(520 - 550) / 550] x 100
Subtract the new number by the original number
520 - 550 = -30
-30 ÷ 550 = -0.05454545454545454
-0.05454545454545454 x 100 = -5.45%