-3.93% is the change from 509 to 489
Calculation steps:
[( 489 - 509 ) ÷ 509] x 100 = -3.93%
Formula
Percentage change = [(489 - 509) / 509] x 100
Subtract the new number by the original number
489 - 509 = -20
-20 ÷ 509 = -0.03929273084479371
-0.03929273084479371 x 100 = -3.93%