-51.24% is the change from 646 to 315
Calculation steps:
[( 315 - 646 ) ÷ 646] x 100 = -51.24%
Formula
Percentage change = [(315 - 646) / 646] x 100
Subtract the new number by the original number
315 - 646 = -331
-331 ÷ 646 = -0.5123839009287926
-0.5123839009287926 x 100 = -51.24%