-17.11% is the change from 830 to 688
Calculation steps:
[( 688 - 830 ) ÷ 830] x 100 = -17.11%
Formula
Percentage change = [(688 - 830) / 830] x 100
Subtract the new number by the original number
688 - 830 = -142
-142 ÷ 830 = -0.1710843373493976
-0.1710843373493976 x 100 = -17.11%