-19.42% is the change from 309 to 249
Calculation steps:
[( 249 - 309 ) ÷ 309] x 100 = -19.42%
Formula
Percentage change = [(249 - 309) / 309] x 100
Subtract the new number by the original number
249 - 309 = -60
-60 ÷ 309 = -0.1941747572815534
-0.1941747572815534 x 100 = -19.42%