The State Auditor shall be appointed by the Senate and General Assembly in joint meeting for a term of five years and until his successor shall be appointed and qualify. It shall be his duty to conduct post-audits of all transactions and accounts kept by or for all departments, offices and agencies of the State government, to report to the Legislature or to any committee thereof as shall be required by law, and to perform such other similar or related duties as shall, from time to time, be required of him by law.