15-30-2102. Construction of income. For the purpose of raising revenue, the income required to be shown on returns under this chapter and taken as the basis for determining the tax may not be classified or held or construed to be property. All income except what has been expressly exempted under the provisions of the Internal Revenue Code or this chapter and income not permitted to be taxed under the constitution of this state or the constitution or laws of the United States must be included and considered in determining the income of taxpayers subject to tax within the provisions of this chapter.