-97.5% is the change from 599 to 15
Calculation steps:
[( 15 - 599 ) ÷ 599] x 100 = -97.5%
Formula
Percentage change = [(15 - 599) / 599] x 100
Subtract the new number by the original number
15 - 599 = -584
-584 ÷ 599 = -0.9749582637729549
-0.9749582637729549 x 100 = -97.5%