-93.75% is the change from 320 to 20
Calculation steps:
[( 20 - 320 ) ÷ 320] x 100 = -93.75%
Formula
Percentage change = [(20 - 320) / 320] x 100
Subtract the new number by the original number
20 - 320 = -300
-300 ÷ 320 = -0.9375
-0.9375 x 100 = -93.75%