-2.25% is the change from 666 to 651
Calculation steps:
[( 651 - 666 ) ÷ 666] x 100 = -2.25%
Formula
Percentage change = [(651 - 666) / 666] x 100
Subtract the new number by the original number
651 - 666 = -15
-15 ÷ 666 = -0.02252252252252252
-0.02252252252252252 x 100 = -2.25%