-18.24% is the change from 340 to 278
Calculation steps:
[( 278 - 340 ) ÷ 340] x 100 = -18.24%
Formula
Percentage change = [(278 - 340) / 340] x 100
Subtract the new number by the original number
278 - 340 = -62
-62 ÷ 340 = -0.18235294117647058
-0.18235294117647058 x 100 = -18.24%