-71.82% is the change from 550 to 155
Calculation steps:
[( 155 - 550 ) ÷ 550] x 100 = -71.82%
Formula
Percentage change = [(155 - 550) / 550] x 100
Subtract the new number by the original number
155 - 550 = -395
-395 ÷ 550 = -0.7181818181818181
-0.7181818181818181 x 100 = -71.82%