10. The employee who receives a pension under the Act respecting the Government and Public Employees Retirement Plan (chapter R-10) or a pension plan or who is entitled to a deferred annuity under the plan prescribed by that Act or a pension plan and who has complied with section 8 is granted, for each of his years of teaching not counted in the plan under that Act or in the pension plan, pension credit equal to 1% of his annual pensionable salary(a) on the date on which he began to receive a pension or became entitled to a deferred annuity, if that date is before 1 July 1977,
(b) as of 30 June 1977, if he has begun to receive a pension or become entitled to a deferred annuity after 30 June 1977.