-40.36% is the change from 991 to 591
Calculation steps:
[( 591 - 991 ) ÷ 991] x 100 = -40.36%
Formula
Percentage change = [(591 - 991) / 991] x 100
Subtract the new number by the original number
591 - 991 = -400
-400 ÷ 991 = -0.4036326942482341
-0.4036326942482341 x 100 = -40.36%