-37.75% is the change from 837 to 521
Calculation steps:
[( 521 - 837 ) ÷ 837] x 100 = -37.75%
Formula
Percentage change = [(521 - 837) / 837] x 100
Subtract the new number by the original number
521 - 837 = -316
-316 ÷ 837 = -0.37753882915173237
-0.37753882915173237 x 100 = -37.75%
Example