The state pension systems for teachers of public education have proved to be inadequate to meet the special needs of retirement during this period of sharply increasing costs of living. A completely adequate retirement system for teachers is an essential responsibility of the state in providing sound public education. Therefore, § 16-15-13 to § 16-15-15 are designed to provide additional state aid for retired teachers in order to make the teaching profession more attractive to qualified teachers and to provide for the security and welfare of education in the state.