Statistics compiled by MAD Magazine Issue 228, January 1982. (Dated but still a relevant source).

40% – Presents.
6% – Presents with no useful functions.
4% – Presents with a function, but which will never be used.
10% – Presents the recipient will say they like, but really hate.
11% – Presents you really want for yourself, and plan to use after the intended recipients get tired of them.
6% – Presents for people you hate, but feel you have to buy for.
* -Presents the recipients will really like.
3% – T-shirts with writings on them.
21% – Decorations.
6% – Christmas tree (less if youre really cheap and wait till Dec. 24th to buy it!).
1% – Christmas tree lights to replace the ones that burned out last year.
1% – Christmas tree lights to replace the ones you stepped on this year.
2% – Christmas tree ornaments.
3% – Christmas tree ornaments hangers (includes the gas for that extra trip you always have to make back to store because there werent enough hangers supplied with the ornaments).
1% – A new star for the top.
2% – Tinsel (which everyone will put on the tree incorrectly, starting a very bad … and possibly violent … family argument).
2% – Outdoor displays.
2% – Medical bills for injuries sustained while putting up outdoor displays.
1% – Fuses to replace those blown when turning on outdoor displays for the first time.
8% – Food and Drink.
1% – More eggnog than the entire Osmond family could even drink.
1.5% – Foods you would never buy any other time of the year (i.e. fruitcakes, mincemeat, etc.).
1% – Alcoholic beverages (triple this figure if you have relatives coming from out of town).
1% – Milk and cookies the kids make leave out for Santa.
1% – Candy canes that nobody ever eats.
2% – Turkey.
0.5% – Antacid.
9% – Entertainment.
1% – That new record you buy every year (even though you already have 27 hours of recorded Christmas music).
3% – Taking a bunch of kids to a really crummy G-rated movie about cute little animals.
5% – Extra trips to the local bar that you take to avoid those sickening TV Christmas Specials the networks keep throwing at you.
12% – Miscellaneous.
3% – Sickly-sweet Christmas Cards.
2% – Postage for same.
2% – Bonuses for people who dont even deserve them (like that louse paper boy).
0.5% – Candles.
0.5% – Plastic mistletoe.
2% – Money tossed into street-corner Santas buckets (although you dont really know what its for).
2% – Money for the collection plate for your once-a-year trip to church for Christmas Mass.
10% – Batteries.

* Too small an amount to be statistically significant.