SDCL § 9-20-8: Percentage of voters required to sign referendum petition--Data concerning signers.

The referendum petition shall be 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. The signer or circulator shall add the signer's residence address, county of voter registration, and date of signing. The signer's post office box number may be given in lieu of a street address if the signer lives within a municipality of the second or third class.