Notwithstanding the provisions of chapter 15-39.1, any person who retired from teaching under the teachers’ insurance and retirement fund prior to July 1, 1971, who had ten or more years of teaching credit under that program is entitled to elect to qualify for benefits under the teachers’ fund for retirement by complying with the provisions of this chapter. A college teacher who retired from teaching after July 1, 1971, may, notwithstanding the provisions of section 15-39.1-25, elect to receive benefits in accordance with chapter 15-39.1 and section 15-39.2-05. The amount of monthly benefits to which an annuitant electing to come under the 1971 law is entitled until death is equal to one and one-half percent of the monthly salary of the annuitant for the last school year for each year of service of that annuitant. Monthly salary within the meaning of this provision is deemed to be an amount equal to one-twelfth of the annual salary of the teacher. If for any reason the earnings of the teacher for the last year of teaching are shown to have been nonrepresentative of the teacher’s typical earnings, the board shall readjust the credit to be allowed for past years of service to the last year of typical earnings. As used in this section, “college teacher” means a retired teacher who is entitled to receive an annuity through the teachers’ insurance and annuity association of America – college retirement equities fund (TIAA-CREF) as a result of having participated in the North Dakota state board of higher education TIAA-CREF retirement plan for North Dakota state institutions of higher education.