3.53% is the change from 821 to 850
Calculation steps:
[( 850 - 821 ) ÷ 821] x 100 = 3.53%
Formula
Percentage change = [(850 - 821) / 821] x 100
Subtract the new number by the original number
850 - 821 = 29
29 ÷ 821 = 0.03532277710109622
0.03532277710109622 x 100 = 3.53%