> Make the table:
> id | year | value
> ---+------+------
> 1 | 1970 | 23
> 1 | 1971 | 25
> 1 | 1972 | 28
> ...
> 2 | 1972 | 5
> 3 | 1971 | 94
> 3 | 1972 | 102
> primary key: (id,year)
> value not null
> and be ready.
>the import/update reasons are pretty easily solved
>that way too.
then your primary key will consists of two fields.
I prefer the primary keys with one field only.
-Franz