The registered voters of any municipality may propose ordinances and resolutions for the government of the municipality if the petition is signed by at least five percent of the registered voters in the municipality. The percentage shall be based on the number of registered voters of the municipality as recorded by the county auditor on the second Tuesday in January in the year the petition is filed. If the petition is filed before the second Tuesday in January, the prior year's calculation of registered voters shall be used.
SDCL 9-20-1