-37.38% is the change from 800 to 501
Calculation steps:
[( 501 - 800 ) ÷ 800] x 100 = -37.38%
Formula
Percentage change = [(501 - 800) / 800] x 100
Subtract the new number by the original number
501 - 800 = -299
-299 ÷ 800 = -0.37375
-0.37375 x 100 = -37.38%