-37.27% is the change from 821 to 515
Calculation steps:
[( 515 - 821 ) ÷ 821] x 100 = -37.27%
Formula
Percentage change = [(515 - 821) / 821] x 100
Subtract the new number by the original number
515 - 821 = -306
-306 ÷ 821 = -0.37271619975639464
-0.37271619975639464 x 100 = -37.27%