-74.77% is the change from 321 to 81
Calculation steps:
[( 81 - 321 ) ÷ 321] x 100 = -74.77%
Formula
Percentage change = [(81 - 321) / 321] x 100
Subtract the new number by the original number
81 - 321 = -240
-240 ÷ 321 = -0.7476635514018691
-0.7476635514018691 x 100 = -74.77%