Only 2, one of which was from the postman!
It seems to be yet another competitive thing - how many cards did you get? are they homemade by some Yummy mummy or their equally ghastly sprog? etc., etc.
The year I turned 60 and got a -minute- pension [I was a kept woman], I sent cards and told everyone that from now on i was cutting back as i was broke and a pensioner. Only about 2 people responded...
My list was endless, friends of my late parents who never wrote, people i hadn't seen for about 30 years and was unlikely to see again. Quite frankly, I also was fed up with the letters about their riches, their perfect DCs and the unbelievably gifted GCs. 
I felt so much better after that. I now send about 5 cards by post, and the rest by e-mail. If they don't like it, they can lump it!
Having said all that, I love Christmas, the build-up, the services, the carols, the church decorations, the food, the whole blooming lot!