-6.69% is the change from 688 to 642
Calculation steps:
[( 642 - 688 ) ÷ 688] x 100 = -6.69%
Formula
Percentage change = [(642 - 688) / 688] x 100
Subtract the new number by the original number
642 - 688 = -46
-46 ÷ 688 = -0.06686046511627906
-0.06686046511627906 x 100 = -6.69%