-17.8% is the change from 309 to 254
Calculation steps:
[( 254 - 309 ) ÷ 309] x 100 = -17.8%
Formula
Percentage change = [(254 - 309) / 309] x 100
Subtract the new number by the original number
254 - 309 = -55
-55 ÷ 309 = -0.1779935275080906
-0.1779935275080906 x 100 = -17.8%