-3.5% is the change from 858 to 828
Calculation steps:
[( 828 - 858 ) ÷ 858] x 100 = -3.5%
Formula
Percentage change = [(828 - 858) / 858] x 100
Subtract the new number by the original number
828 - 858 = -30
-30 ÷ 858 = -0.03496503496503497
-0.03496503496503497 x 100 = -3.5%