-16.73% is the change from 771 to 642
Calculation steps:
[( 642 - 771 ) ÷ 771] x 100 = -16.73%
Formula
Percentage change = [(642 - 771) / 771] x 100
Subtract the new number by the original number
642 - 771 = -129
-129 ÷ 771 = -0.16731517509727625
-0.16731517509727625 x 100 = -16.73%