Goal difference

I always tend to think that worst goal difference = worst teams. Sad old b######d that I am but I have just been looking at recent years in the Premier league. In the last five years the three teams with the worst goal difference have always gone down. Except once when Wigan stayed up by one point. I hope to God we can buck the trend BUT invarably the three teams with the worst goal difference go down!
That would send us, Fulham and Norwich to the Championship with Sunderland escaping!