-1.38% is the change from 651 to 642
Calculation steps:
[( 642 - 651 ) ÷ 651] x 100 = -1.38%
Formula
Percentage change = [(642 - 651) / 651] x 100
Subtract the new number by the original number
642 - 651 = -9
-9 ÷ 651 = -0.013824884792626729
-0.013824884792626729 x 100 = -1.38%