-89.04% is the change from 821 to 90
Calculation steps:
[( 90 - 821 ) ÷ 821] x 100 = -89.04%
Formula
Percentage change = [(90 - 821) / 821] x 100
Subtract the new number by the original number
90 - 821 = -731
-731 ÷ 821 = -0.8903775883069428
-0.8903775883069428 x 100 = -89.04%