-2.51% is the change from 838 to 817
Calculation steps:
[( 817 - 838 ) ÷ 838] x 100 = -2.51%
Formula
Percentage change = [(817 - 838) / 838] x 100
Subtract the new number by the original number
817 - 838 = -21
-21 ÷ 838 = -0.025059665871121718
-0.025059665871121718 x 100 = -2.51%