-97.6% is the change from 624 to 15
Calculation steps:
[( 15 - 624 ) ÷ 624] x 100 = -97.6%
Formula
Percentage change = [(15 - 624) / 624] x 100
Subtract the new number by the original number
15 - 624 = -609
-609 ÷ 624 = -0.9759615384615384
-0.9759615384615384 x 100 = -97.6%