-51.29% is the change from 657 to 320
Calculation steps:
[( 320 - 657 ) ÷ 657] x 100 = -51.29%
Formula
Percentage change = [(320 - 657) / 657] x 100
Subtract the new number by the original number
320 - 657 = -337
-337 ÷ 657 = -0.512937595129376
-0.512937595129376 x 100 = -51.29%