The numbers are fudged by a very small amount in a certain direction, based on my observation. I observed this by refreshing one of my own submissions and watching it gain a vote or lose a vote, and I knew exactly how many people had voted on it because it was in a purpose-created subreddit. One of the admins that lurks Hacker News can probably set us straight on which is correct.
I love that whenever I make a comment here even loosely related to Reddit, someone takes it upon themselves to assume that I've never even been to the site and condescend based on what they think they know. My comment wasn't even remotely about Reddit, but thanks for the correction.
Displayed numbers: 9498 Up, 6876 Down.
Real numbers: 2666 Up, 140 Down.
You cannot judge proportion by looking at the numbers Reddit shows.