-3.5% is the change from 829 to 800
Calculation steps:
[( 800 - 829 ) ÷ 829] x 100 = -3.5%
Formula
Percentage change = [(800 - 829) / 829] x 100
Subtract the new number by the original number
800 - 829 = -29
-29 ÷ 829 = -0.03498190591073583
-0.03498190591073583 x 100 = -3.5%