-39.72% is the change from 647 to 390
Calculation steps:
[( 390 - 647 ) ÷ 647] x 100 = -39.72%
Formula
Percentage change = [(390 - 647) / 647] x 100
Subtract the new number by the original number
390 - 647 = -257
-257 ÷ 647 = -0.3972179289026275
-0.3972179289026275 x 100 = -39.72%