-16.1% is the change from 621 to 521
Calculation steps:
[( 521 - 621 ) ÷ 621] x 100 = -16.1%
Formula
Percentage change = [(521 - 621) / 621] x 100
Subtract the new number by the original number
521 - 621 = -100
-100 ÷ 621 = -0.1610305958132045
-0.1610305958132045 x 100 = -16.1%