-3.38% is the change from 857 to 828
Calculation steps:
[( 828 - 857 ) ÷ 857] x 100 = -3.38%
Formula
Percentage change = [(828 - 857) / 857] x 100
Subtract the new number by the original number
828 - 857 = -29
-29 ÷ 857 = -0.0338389731621937
-0.0338389731621937 x 100 = -3.38%