The commissioner of school and public lands may select not more than fifty thousand acres from the school and endowment lands of the state, to be offered for sale in each fiscal year. However, in counties in which unsold school land amounts to more than five percent of the total acreage of the county, no more than twenty percent of the total acreage of such school land may be offered for sale, in any one year.
SDCL 5-9-1