It would be even more interesting to look at it over ten or twenty years. This would say a lot about the fundamental competitiveness of each club.
Well i am bored so ill answer it for you
between 2000-2009 we had the 4th best win% of all teams with 54%.
Out of the 8 teams to have to had a more then 50% record only us and dragons didnt win a comp. The dragons won it a year later.
Penrith and wests tigers won a comp in that period but were pretty ordinary.
Penrith had 46.61%
Wests Tigers 43.35%.
Since 2000 if you include everyones record since then it leaves only 6 teams that have a 50% win record. Melbourne, Roosters, Brisbane, Manly, Canterbury and Penrith scrape in on the back of their last 2 seasons
Parramatta are ranked 8th out of the current 16 teams with a 49% winning record