-3.49% is the change from 860 to 830
Calculation steps:
[( 830 - 860 ) ÷ 860] x 100 = -3.49%
Formula
Percentage change = [(830 - 860) / 860] x 100
Subtract the new number by the original number
830 - 860 = -30
-30 ÷ 860 = -0.03488372093023256
-0.03488372093023256 x 100 = -3.49%