-49.33% is the change from 671 to 340
Calculation steps:
[( 340 - 671 ) ÷ 671] x 100 = -49.33%
Formula
Percentage change = [(340 - 671) / 671] x 100
Subtract the new number by the original number
340 - 671 = -331
-331 ÷ 671 = -0.4932935916542474
-0.4932935916542474 x 100 = -49.33%