-80.85% is the change from 423 to 81
Calculation steps:
[( 81 - 423 ) ÷ 423] x 100 = -80.85%
Formula
Percentage change = [(81 - 423) / 423] x 100
Subtract the new number by the original number
81 - 423 = -342
-342 ÷ 423 = -0.8085106382978723
-0.8085106382978723 x 100 = -80.85%