-5.88% is the change from 340 to 320
Calculation steps:
[( 320 - 340 ) ÷ 340] x 100 = -5.88%
Formula
Percentage change = [(320 - 340) / 340] x 100
Subtract the new number by the original number
320 - 340 = -20
-20 ÷ 340 = -0.058823529411764705
-0.058823529411764705 x 100 = -5.88%