-93.4% is the change from 318 to 21
Calculation steps:
[( 21 - 318 ) ÷ 318] x 100 = -93.4%
Formula
Percentage change = [(21 - 318) / 318] x 100
Subtract the new number by the original number
21 - 318 = -297
-297 ÷ 318 = -0.9339622641509434
-0.9339622641509434 x 100 = -93.4%