-13.04% is the change from 391 to 340
Calculation steps:
[( 340 - 391 ) ÷ 391] x 100 = -13.04%
Formula
Percentage change = [(340 - 391) / 391] x 100
Subtract the new number by the original number
340 - 391 = -51
-51 ÷ 391 = -0.13043478260869565
-0.13043478260869565 x 100 = -13.04%