-3.23% is the change from 651 to 630
Calculation steps:
[( 630 - 651 ) ÷ 651] x 100 = -3.23%
Formula
Percentage change = [(630 - 651) / 651] x 100
Subtract the new number by the original number
630 - 651 = -21
-21 ÷ 651 = -0.03225806451612903
-0.03225806451612903 x 100 = -3.23%