The county auditor shall maintain and safeguard a file of voters in computer format that contains the information of each person registered in each voting precinct within the county. This file shall be known as the master registration file and shall and must be, at all times during office hours, open to public inspection. However, public access to social security numbers, driver license numbers, and dates of birth contained in the master registration file is prohibited. The master registration file shall contain contains all information from each voter's registration card. The master registration file shall alsoinclude includes the date of the last election in which the voter has voted in and when the voter's information was last updated. The master registration file may also contain additional voter history information. Any The county auditor shall maintain any voter registration form for a purged or unregistered voter shall be kept for twenty-two months. No purged or unregistered voter may be included in the master registration file. Each county auditor shall update the county's file twice each year, including no less than sixty days before a general election.