-1.57% is the change from 509 to 501
Calculation steps:
[( 501 - 509 ) ÷ 509] x 100 = -1.57%
Formula
Percentage change = [(501 - 509) / 509] x 100
Subtract the new number by the original number
501 - 509 = -8
-8 ÷ 509 = -0.015717092337917484
-0.015717092337917484 x 100 = -1.57%