-66.01% is the change from 509 to 173
Calculation steps:
[( 173 - 509 ) ÷ 509] x 100 = -66.01%
Formula
Percentage change = [(173 - 509) / 509] x 100
Subtract the new number by the original number
173 - 509 = -336
-336 ÷ 509 = -0.6601178781925344
-0.6601178781925344 x 100 = -66.01%