-50.87% is the change from 690 to 339
Calculation steps:
[( 339 - 690 ) ÷ 690] x 100 = -50.87%
Formula
Percentage change = [(339 - 690) / 690] x 100
Subtract the new number by the original number
339 - 690 = -351
-351 ÷ 690 = -0.508695652173913
-0.508695652173913 x 100 = -50.87%