-1.5% is the change from 800 to 788
Calculation steps:
[( 788 - 800 ) ÷ 800] x 100 = -1.5%
Formula
Percentage change = [(788 - 800) / 800] x 100
Subtract the new number by the original number
788 - 800 = -12
-12 ÷ 800 = -0.015
-0.015 x 100 = -1.5%
Example