The taxation and revenue department, in cooperation with the international association of assessing officers and the real estate appraisers board, may establish four grades of courses in the field of property valuation and property tax administration. The courses shall be graded in order of increasing difficulty and shall be administered by the department. Persons completing a course and passing an examination on a particular grade of property valuation and property tax administration shall be issued an appraiser’s certificate of an appropriate grade. A person shall not be issued an appraiser’s certificate of a particular grade unless the person has been issued an appraiser’s certificate for each one of the lesser grades. The appraiser’s certificates shall be denominated “Appraiser 1”, “Appraiser 2”, “Appraiser 3” and “Appraiser 4” and shall be granted in order of difficulty of the course and examination completed. The “Appraiser 4” certificate shall be granted for completion of the most difficult course. County assessors or appraisers who have been granted an “Appraiser 4” certificate shall be designated “New Mexico certified appraiser” and shall be provided by the taxation and revenue department with a certificate granting this designation.