-26.47% is the change from 340 to 250
Calculation steps:
[( 250 - 340 ) ÷ 340] x 100 = -26.47%
Formula
Percentage change = [(250 - 340) / 340] x 100
Subtract the new number by the original number
250 - 340 = -90
-90 ÷ 340 = -0.2647058823529412
-0.2647058823529412 x 100 = -26.47%