The office of county tax assessor-collector is constitutionally required for counties with a population exceeding 10,000. In smaller counties the duties of the office may be carried out by the sheriff. The Constitution of 1876 specifies that the county tax assessor-collector be elected biennially; however, in 1954 a constitutional amendment changed the term of office to four years. The duties of the office have included both the determination of property values and the collection of taxes, but in 1982 the appraisal duties were reassigned to the chief appraiser of the district. The county tax assessor-collector is also responsible for motor-vehicle registration and voter registration.