-6.51% is the change from 307 to 287
Calculation steps:
[( 287 - 307 ) ÷ 307] x 100 = -6.51%
Formula
Percentage change = [(287 - 307) / 307] x 100
Subtract the new number by the original number
287 - 307 = -20
-20 ÷ 307 = -0.06514657980456026
-0.06514657980456026 x 100 = -6.51%