WOW, outsiders bought 30% of all homes purchased in Hawaii since 2007? Can you provide some research the substantiates your position? If them outsiders are driving up prices because they're buying up property how much are you gonna raise property taxes to make em stop? 
Since you've looking into this gotta ask why them outsiders are paying millions to buy a house in Hawaii when they could get a bigger house for a fraction on the price in Florida or any state on the Gulf Coast. We don't have a monopoly on sun, sand and surf. Them property taxes in Florida, Texas and other states with beaches must really be a bunch to make them outsiders pay triple to buy here..