-80.5% is the change from 400 to 78
Calculation steps:
[( 78 - 400 ) ÷ 400] x 100 = -80.5%
Formula
Percentage change = [(78 - 400) / 400] x 100
Subtract the new number by the original number
78 - 400 = -322
-322 ÷ 400 = -0.805
-0.805 x 100 = -80.5%
Example