Nat Ins Record - No Full Years when in receipt of child benefit

I have a relative who has 5 children and has been in receipt of a small state pension. I would have expected the pension to be bigger given you are supposed to be credited with full years NIC contribution for years claiming child benefit. Her first born was June 1966 and fourth born Sept 89. Fifth born late child was Jan 87. So would that make 36 years in receipt of child benefit. Her Nat Ins record shows 2 full years up to 5 April 1975. From April 1975 to 2006 shows year is not full. 2006 to 2009 shows fully years which can only be from child benefit. I think 1975 was when full year credit started to be given for Child Benefit. So should her years from 1976 to 2006 have been full years? If this is the case is it too late to do anything about this. I have not told the relative anything about this as don't want to build up any hope which might be false.

Hi,
Although your relative may have been in receipt of child benefit payments, the credits are only available from 06/04/1978 onwards.
The ‘credits’ were available until the child turned 16 years of age, however, if your relative reached State Pension Age (SPA) before 6 April 2010, the credits worked by reducing the number of qualifying years they needed for the full basic State Pension up to a maximum of 22 years, instead of receiving a qualifying year credit.
Furthermore, your relative was not entitled to credits for a period they were a married woman and paid the reduced rate of National Insurance.
Please get your relative to call us on 0300 200 3500 to discuss eligibility based on their National Insurance record and how to apply, in relation to the above circumstances. 
Thank you.