Neb. Rev. Stat. §§ 46-195
If a majority of the votes cast are in favor of issuing such bonds, the board of directors shall immediately cause bonds in such amount to be issued. The bonds shall be payable in lawful money of the United States, as follows: At the expiration of eleven years not less than five percent of the bonds; at the expiration of twelve years, not less than six percent; at the expiration of thirteen years, not less than seven percent; at the expiration of fourteen years, not less than eight percent; at the expiration of fifteen years, not less than nine percent; at the expiration of sixteen years, not less than ten percent; at the expiration of seventeen years, not less than eleven percent; at the expiration of eighteen years, not less than thirteen percent; at the expiration of nineteen years, not less than fifteen percent; and for the twentieth year a percentage sufficient to pay off the bonds. Any such district may by a majority vote provide for the issuance of bonds that will mature in any number of years less than twenty, and arrange for the payment thereof in installments at the same ratio as above provided. The district may also, at its option, redeem any bonds issued at any time on or after five years from the date of issuance thereof.
Neb. Rev. Stat. §§ 46-195