(1) Subject to this Act, a person shall be entitled to old age (contributory) pension if he has attained pensionable age and satisfies the contribution conditions in section 84.
"yearly average" means, in relation to any claimant, the average per contribution year of contribution weeks in respect of which that claimant has qualifying contributions, voluntary contributions or credited contributions in the period commencing either - (a) on the 5th day of January, 1953, in case the claimant is a man, or on the 6th day of July, 1953, in case the claimant is a woman, or (b) at the beginning of the contribution year in which the claimant's entry into insurance occurred (if after the 5th day of January, 1953, in the case of a man, or the 6th day of July, 1953, in the case of a woman) (whichever is the later) and ending at the end of the last complete contribution year before the date of his attaining pensionable age;
"alternative yearly average" means,