-43.64% is the change from 550 to 310
Calculation steps:
[( 310 - 550 ) ÷ 550] x 100 = -43.64%
Formula
Percentage change = [(310 - 550) / 550] x 100
Subtract the new number by the original number
310 - 550 = -240
-240 ÷ 550 = -0.43636363636363634
-0.43636363636363634 x 100 = -43.64%