-97.83% is the change from 830 to 18
Calculation steps:
[( 18 - 830 ) ÷ 830] x 100 = -97.83%
Formula
Percentage change = [(18 - 830) / 830] x 100
Subtract the new number by the original number
18 - 830 = -812
-812 ÷ 830 = -0.9783132530120482
-0.9783132530120482 x 100 = -97.83%