-4.1% is the change from 512 to 491
Calculation steps:
[( 491 - 512 ) ÷ 512] x 100 = -4.1%
Formula
Percentage change = [(491 - 512) / 512] x 100
Subtract the new number by the original number
491 - 512 = -21
-21 ÷ 512 = -0.041015625
-0.041015625 x 100 = -4.1%