<a target=_blank class=ftalternatingbarlinklarge href="http://en.wikipedia.org/wiki/Blood_type
">http://en.wikipedia.org/wiki/Blood_type
</a>
If you look at this wikipedia article on blood type, you will see some interesting facts about how blood types are distributed across the globe. When countries and populations were a little more isolated, blood types were too. Now, not so much.
O is often the most common blood type in a given country, but Northern Europeans have a slightly higher tendency toward A, so you may see more people with CF with A and O blood types.
As far as I know, there has never been any documented link to the CFTR gene mutation and blood type though.