-9.45% is the change from 307 to 278
Calculation steps:
[( 278 - 307 ) ÷ 307] x 100 = -9.45%
Formula
Percentage change = [(278 - 307) / 307] x 100
Subtract the new number by the original number
278 - 307 = -29
-29 ÷ 307 = -0.09446254071661238
-0.09446254071661238 x 100 = -9.45%