Maine state taxe for nonresident

I'm following the prompts for Main state tax.  I'm a nonresident that worked partly inside and out of the state.

 

The page on my screen says "Income Allocation" and asks for "Portion of Wages to be Allocated".   What do I put in there?

 

My assumption is to enter a percentage or dollar amount for how much money I made in Maine?  However the page doesnt have any links to anything that helps me know what it is asking for.

 

Can anyone help me out?