-30.61% is the change from 490 to 340
Calculation steps:
[( 340 - 490 ) ÷ 490] x 100 = -30.61%
Formula
Percentage change = [(340 - 490) / 490] x 100
Subtract the new number by the original number
340 - 490 = -150
-150 ÷ 490 = -0.30612244897959184
-0.30612244897959184 x 100 = -30.61%