-23.66% is the change from 837 to 639
Calculation steps:
[( 639 - 837 ) ÷ 837] x 100 = -23.66%
Formula
Percentage change = [(639 - 837) / 837] x 100
Subtract the new number by the original number
639 - 837 = -198
-198 ÷ 837 = -0.23655913978494625
-0.23655913978494625 x 100 = -23.66%