-50.86% is the change from 991 to 487
Calculation steps:
[( 487 - 991 ) ÷ 991] x 100 = -50.86%
Formula
Percentage change = [(487 - 991) / 991] x 100
Subtract the new number by the original number
487 - 991 = -504
-504 ÷ 991 = -0.508577194752775
-0.508577194752775 x 100 = -50.86%