-2.75% is the change from 800 to 778
Calculation steps:
[( 778 - 800 ) ÷ 800] x 100 = -2.75%
Formula
Percentage change = [(778 - 800) / 800] x 100
Subtract the new number by the original number
778 - 800 = -22
-22 ÷ 800 = -0.0275
-0.0275 x 100 = -2.75%