Can I allocate 50% of income from a joint account to one spouse in Maryland

We live in MD and I am completing our return.  I am being asked how much of our cap gain income and fed exempt investment income is attributable to each spouse.  The accounts are held jointly.   If I allocate all to one person, we get a $7 deduction.  If I allocate it 50/50, we get a $1200 deduction so this is material.