-20.94% is the change from 320 to 253
Calculation steps:
[( 253 - 320 ) ÷ 320] x 100 = -20.94%
Formula
Percentage change = [(253 - 320) / 320] x 100
Subtract the new number by the original number
253 - 320 = -67
-67 ÷ 320 = -0.209375
-0.209375 x 100 = -20.94%