-97.89% is the change from 993 to 21
Calculation steps:
[( 21 - 993 ) ÷ 993] x 100 = -97.89%
Formula
Percentage change = [(21 - 993) / 993] x 100
Subtract the new number by the original number
21 - 993 = -972
-972 ÷ 993 = -0.9788519637462235
-0.9788519637462235 x 100 = -97.89%