-97.05% is the change from 509 to 15
Calculation steps:
[( 15 - 509 ) ÷ 509] x 100 = -97.05%
Formula
Percentage change = [(15 - 509) / 509] x 100
Subtract the new number by the original number
15 - 509 = -494
-494 ÷ 509 = -0.9705304518664047
-0.9705304518664047 x 100 = -97.05%