-57.62% is the change from 991 to 420
Calculation steps:
[( 420 - 991 ) ÷ 991] x 100 = -57.62%
Formula
Percentage change = [(420 - 991) / 991] x 100
Subtract the new number by the original number
420 - 991 = -571
-571 ÷ 991 = -0.5761856710393541
-0.5761856710393541 x 100 = -57.62%