-37.04% is the change from 810 to 510
Calculation steps:
[( 510 - 810 ) ÷ 810] x 100 = -37.04%
Formula
Percentage change = [(510 - 810) / 810] x 100
Subtract the new number by the original number
510 - 810 = -300
-300 ÷ 810 = -0.37037037037037035
-0.37037037037037035 x 100 = -37.04%