-50.8% is the change from 691 to 340
Calculation steps:
[( 340 - 691 ) ÷ 691] x 100 = -50.8%
Formula
Percentage change = [(340 - 691) / 691] x 100
Subtract the new number by the original number
340 - 691 = -351
-351 ÷ 691 = -0.507959479015919
-0.507959479015919 x 100 = -50.8%