-7.8% is the change from 641 to 591
Calculation steps:
[( 591 - 641 ) ÷ 641] x 100 = -7.8%
Formula
Percentage change = [(591 - 641) / 641] x 100
Subtract the new number by the original number
591 - 641 = -50
-50 ÷ 641 = -0.078003120124805
-0.078003120124805 x 100 = -7.8%