-17.8% is the change from 781 to 642
Calculation steps:
[( 642 - 781 ) ÷ 781] x 100 = -17.8%
Formula
Percentage change = [(642 - 781) / 781] x 100
Subtract the new number by the original number
642 - 781 = -139
-139 ÷ 781 = -0.17797695262483995
-0.17797695262483995 x 100 = -17.8%