-69.55% is the change from 509 to 155
Calculation steps:
[( 155 - 509 ) ÷ 509] x 100 = -69.55%
Formula
Percentage change = [(155 - 509) / 509] x 100
Subtract the new number by the original number
155 - 509 = -354
-354 ÷ 509 = -0.6954813359528488
-0.6954813359528488 x 100 = -69.55%