Understanding 'Full year' N.I. contributions

Undeuxtrois

I know I cannot make any voluntary contributions for years before 2006.

But back in year ending 1988, I have a 'full year' with 27 weeks of contributions, but later in 1991, I apparently have 37 weeks of N.I. credits but the Year is not full (doesn't count to pension). Is this correct and why is this?

Thanks for any help understanding this

molerat

How does it state those "weeks" were gained ? Employed contributions are just quoted as £ with no weeks, credits from earning above the LEL are not mentioned at all, again with no weeks.  Weeks are usually only mentioned where they are gained from benefits or voluntary contributions. So yes you can have a full year with only part of that year showing a reason and not a full year for the same reason.