-17.56% is the change from 780 to 643
Calculation steps:
[( 643 - 780 ) ÷ 780] x 100 = -17.56%
Formula
Percentage change = [(643 - 780) / 780] x 100
Subtract the new number by the original number
643 - 780 = -137
-137 ÷ 780 = -0.17564102564102563
-0.17564102564102563 x 100 = -17.56%