-50.72% is the change from 690 to 340
Calculation steps:
[( 340 - 690 ) ÷ 690] x 100 = -50.72%
Formula
Percentage change = [(340 - 690) / 690] x 100
Subtract the new number by the original number
340 - 690 = -350
-350 ÷ 690 = -0.5072463768115942
-0.5072463768115942 x 100 = -50.72%