-20.51% is the change from 780 to 620
Calculation steps:
[( 620 - 780 ) ÷ 780] x 100 = -20.51%
Formula
Percentage change = [(620 - 780) / 780] x 100
Subtract the new number by the original number
620 - 780 = -160
-160 ÷ 780 = -0.20512820512820512
-0.20512820512820512 x 100 = -20.51%