-17.61% is the change from 511 to 421
Calculation steps:
[( 421 - 511 ) ÷ 511] x 100 = -17.61%
Formula
Percentage change = [(421 - 511) / 511] x 100
Subtract the new number by the original number
421 - 511 = -90
-90 ÷ 511 = -0.1761252446183953
-0.1761252446183953 x 100 = -17.61%