-98.49% is the change from 993 to 15
Calculation steps:
[( 15 - 993 ) ÷ 993] x 100 = -98.49%
Formula
Percentage change = [(15 - 993) / 993] x 100
Subtract the new number by the original number
15 - 993 = -978
-978 ÷ 993 = -0.9848942598187311
-0.9848942598187311 x 100 = -98.49%