Does Missouri count all of my income as a non resident even if most of the income was earned in Nebraska?

I've already filed my Nebraska state return with a refund of which I am responsible for 1/3.  I only earned $1714 in Missouri but it appears it's taxing me on the $65000 I earned in Nebraska at a rate of 3%.  Is this correct?  I have lived in Nebraska the entire time, only working as a grader for 1 week in Missouri.