Time warrants in newly created counties; payment of interest and creation of sinking fund.

The board of county commissioners of each county issuing such interest-bearing time warrants may pay from the general revenue fund of such county each year the accrued interest on such interest-bearing time warrants to the holders thereof, and they shall set aside from the general revenue fund of such county such sum each year as a sinking fund, which together with accrued interest thereon will be sufficient to pay at least one-fifth of the amount due and required to pay off the said warrants at the end of the said 5-year period, thereby creating a sinking fund during the said period of 5 years sufficient to pay off the entire obligation at the end of the said 5-year period.