-83.47% is the change from 490 to 81
Calculation steps:
[( 81 - 490 ) ÷ 490] x 100 = -83.47%
Formula
Percentage change = [(81 - 490) / 490] x 100
Subtract the new number by the original number
81 - 490 = -409
-409 ÷ 490 = -0.8346938775510204
-0.8346938775510204 x 100 = -83.47%