Interesting question and we thought we'd be able to get the answer from the Las Vegas Convention & Visitor Authority's annual Las Vegas Visitor Profile report. We have a query in to them to see if they can come up with more data, but for now, turns out the report only gives point-of-origin demographic data in broad sweeps.
For the calendar year 2008, 85% of visitors were from the U.S., with 8% of those coming from eastern states, 13% from southern states, 12% from midwestern states, 52% from western states (of which 28% were from California, primarily southern California, and 9% were from Arizona). The other 15% of visitors were from foreign countries.
Out of interest, we then took a look at visitation statistics to our own site for the month of May 2009. What follows is demographic information about the number of hits from different locales, not unique visitors, and the typical profile of visitors to our site is not the same as typical visitation to Las Vegas. Nonetheless, it's an interesting indication of people looking into Las Vegas and where they are, or at least where they were in May. Here's what we found:
Next, with 1% each, came a whole heap of cities beginning with Phoenix, San Diego, Milwaukee, Seattle, Minneapolis, Columbus, Atlanta, and Austin, with Tampa, Beverly Hills, and Broward County at the bottom of the list (but not of the heap -- we love you all!)
Update 6/15/09: Yep, we're updating ourselves before this runs. The above was penned on 6/13 but today we heard back from the very helpful Senior Research Analyst at the LVCVA, who sent us all of their demographic information on airline passengers for 2007 (the '08 data won't be available until later this month -- we'll post an update to this update once we get it). This is the original report from whence your figure about Hawaii being the seventh-largest market originated.
As our September, 2008 Reader Poll about your modes of transport when visiting Las Vegas showed, the majority of our readers fly, as do most others. But there's still a significant number of visitors who drive to Vegas, especially from California, so you can assume that these airline-passenger figures downplay slightly the statistics for some cities (particularly in southern California). Here's the Top 10:
*Includes Burbank, Los Angeles, Ontario, Long Beach, and Orange County **Includes Oakland, San Francisco, and San Jose ***Includes New York, Long Island, and Newark
As far as the Top 10 states are concerned, visitation breaks down thusly:
