-40.31% is the change from 511 to 305
Calculation steps:
[( 305 - 511 ) ÷ 511] x 100 = -40.31%
Formula
Percentage change = [(305 - 511) / 511] x 100
Subtract the new number by the original number
305 - 511 = -206
-206 ÷ 511 = -0.40313111545988256
-0.40313111545988256 x 100 = -40.31%