-61.38% is the change from 800 to 309
Calculation steps:
[( 309 - 800 ) ÷ 800] x 100 = -61.38%
Formula
Percentage change = [(309 - 800) / 800] x 100
Subtract the new number by the original number
309 - 800 = -491
-491 ÷ 800 = -0.61375
-0.61375 x 100 = -61.38%