-15.97% is the change from 770 to 647
Calculation steps:
[( 647 - 770 ) ÷ 770] x 100 = -15.97%
Formula
Percentage change = [(647 - 770) / 770] x 100
Subtract the new number by the original number
647 - 770 = -123
-123 ÷ 770 = -0.15974025974025974
-0.15974025974025974 x 100 = -15.97%