The methods and procedures by which municipal debt is issued are governed by an extensive system of laws and regulations, which vary by state. Most bonds bear interest at either a fixed or variable rate of interest, which can be subject to a cap known as the maximum legal limit; some bonds may be issued solely at an original issue discount, or 0% coupon. If a bond measure is proposed in a local election, a Tax Rate Statement may be provided to voters, detailing best estimates of the tax rate required to levy and fund the bond. In cases where no election is held, depending on applicable local law, voters may be entitled to petition the approval to referendum (i.e., a public vote) within a specified period of time; bonds are typically not issued prior to the expiration of any such referendum period.