-60% is the change from 510 to 204
Calculation steps:
[( 204 - 510 ) ÷ 510] x 100 = -60%
Formula
Percentage change = [(204 - 510) / 510] x 100
Subtract the new number by the original number
204 - 510 = -306
-306 ÷ 510 = -0.6
-0.6 x 100 = -60%
Example