Of the cruises I've been able to account for, going back to '98, 95.02% have been able to dock. Since 2002, that number is 95.01%, and that represents almost 3/4 of all cruises.
Now, in 2005, there have already been three misses, and the overall number is 89.29%. I would expect that number to go up as the sample size increases, but even so, it is certainly better odds than a coin flip.
Totals for the past few years:
2001: 94.12%
2002: 96.77%
2003: 96.61%
2004: 93.22%
Many of the 2004 misses were due to hurricane damage and not necessarily to weather/sea conditions. On several cruises last fall, the ship didn't even attempt to dock. But a miss is still a miss, so I've counted these in the final numbers.
It's been contended that conditions must be perfect in order for the ship to dock. I would say that's debatable, but even conceding that, the numbers indicate that the conditions are perfect almost all of the time.
I believe that they would have had to do a lot of research in to the prevailing winds and currents, etc., to determine the most advantageous position on the island for the pier. There was no development on the island, so it's not as if they had to place the pier near any existing structures for convenience's sake. I have been told that they had to blast the limestone on the ocean floor in order to create the channel. The pier's construction was a considerable expense, and as such it would stand to reason that the goal would be to make it as accessible as possible. This is mostly supposition on my part, but I think it makes more sense than to suppose that they just threw a dart at the map and said, "build the pier here." If you had several million dollars to sink in to such a project, which option would you choose?
To suggest that it is set up poorly based on a single instance of failing to dock is like suggesting that a shortstop in baseball should play behind the plate because the last batter just popped up there. If you watch enough baseball, you know that there will be more balls hit to short than popups behind the plate. By the same token, if you study the wind, weather and currents, you can probably make a reasonable determination as to where the best place to build a cruise ship pier on a given island would be.