-81.63% is the change from 490 to 90
Calculation steps:
[( 90 - 490 ) ÷ 490] x 100 = -81.63%
Formula
Percentage change = [(90 - 490) / 490] x 100
Subtract the new number by the original number
90 - 490 = -400
-400 ÷ 490 = -0.8163265306122449
-0.8163265306122449 x 100 = -81.63%