-49.1% is the change from 1000 to 509
Calculation steps:
[( 509 - 1000 ) ÷ 1000] x 100 = -49.1%
Formula
Percentage change = [(509 - 1000) / 1000] x 100
Subtract the new number by the original number
509 - 1000 = -491
-491 ÷ 1000 = -0.491
-0.491 x 100 = -49.1%