-21.04% is the change from 637 to 503
Calculation steps:
[( 503 - 637 ) ÷ 637] x 100 = -21.04%
Formula
Percentage change = [(503 - 637) / 637] x 100
Subtract the new number by the original number
503 - 637 = -134
-134 ÷ 637 = -0.21036106750392464
-0.21036106750392464 x 100 = -21.04%