77-6-503. Leases of city lots, town lots, and commercial property. The fair rental value of state-owned town lots, city lots, and land valuable for commercial development must be determined from time to time by the department with the approval of the board, and a record must be made of the values. State-owned town lots, city lots, or land valuable for commercial development may be leased at the current appraised rental value for terms not to exceed 99 years.