Rents and royalties from real or tangible personal property, capital gains, interest, dividends, or patent or copyright royalties, to the extent that they constitute nonbusiness income, shall be allocated as provided in Kan. Stat. Ann. §§ 79-3275 to 79-3278, inclusive, and amendments thereto. Allocable nonbusiness income shall be limited to the total nonbusiness income received which is in excess of any related expenses which have been allowed as a deduction during the income year.