Alaska's stingy rich folk

The New York Times has an article today about the relative generosity, in terms of philanthropic activity, of the wealthy people in the various states, based not just on their annual income, but on their total assets. The article focuses on the differences between the coastal/southwestern states and the midwestern/southern states. But also note that the research done by the NewTithing Group reveals that the state that is last on the list, i.e. the state whose residents give the lowest percentage of their total assets, is Alaska. I wonder why--ideas?