Taxation under the Empire amounted to about 5% of the Empire's gross product. The typical tax rate paid by individuals ranged from 2 to 5%. The tax code was "bewildering" in its complicated system of direct and indirect taxes, some paid in cash and some in kind. Taxes might be specific to a province, or kinds of properties such as fisheries or salt evaporation ponds; they might be in effect for a limited time. Tax collection was justified by the need to maintain the military, and taxpayers sometimes got a refund if the army captured a surplus of booty. In-kind taxes were accepted from less-monetized areas, particularly those who could supply grain or goods to army camps.