I'd say probably 60% at least. A lot of the times for me its just like an initial humorous reaction to clear up something that was taken the wrong way or I saw a joke in. In terms of stuff that really gets me laughing it would be much smaller.
I do do a little chuckle or laugh a majority of the time when I post a lol( included Haha's in there as well)
My cold, snide, intellectual life is just a veneer, behind which lies the plywood of loneliness.