500,000 US visitors to Aruba in one year? The Aruba Travel Bureau stats show @ 36,000 US visitors in the high season month of January, 2003, the last reported month. If the high season last five months that would be 180,000 total during the season. I doubt that the off season months (half of which is hurricane season) totals equal 75% of that number.
Well, whatever....I still think that a large chunk of the island's tourists come from the U.S.
Not challenging your figures, just pointing out that one of Aruba's selling points is its southern Caribbean location that is very rarely impacted by hurricanes.