-22.73% is the change from 827 to 639
Calculation steps:
[( 639 - 827 ) ÷ 827] x 100 = -22.73%
Formula
Percentage change = [(639 - 827) / 827] x 100
Subtract the new number by the original number
639 - 827 = -188
-188 ÷ 827 = -0.22732769044740025
-0.22732769044740025 x 100 = -22.73%