"(a)    Three-sevenths of the proceeds of internal revenue taxes due from proprietors or operators of rope factories, sugar centrals, rice mills, corn mills, coconut oil mills, and desiccated coconut factories prescribed in section one hundred and eighty-nine of said Code shall accrue to the provinces, one-seventh to the municipal governments, and the remaining three-sevenths to the National Government. The apportionment of the provincial and municipal allotments shall be based on population as shown by the latest official census.

"(b)    Two per centum of the proceeds of the tax on income shall accrue to the provinces, one per centum to the municipalities and the remainder to the National Government."