"The Dartmouth Atlas Project works to accurately describe how medical resources are distributed and used in the United States. .... the project has demonstrated glaring variations in how health care is delivered across the United States." For a critique of the Dartmouth Atlas methodology, see: Abelson, R and Harris G. (2010, June 3). Critics Question Study Cited in Health Debate. New York Times. pp. A1.
PubMed (with Dickinson Links) includes references to journal articles, but many of these are research articles that may include statistics. Add the word "statistics" to your topic search (for example, asthma AND statistics) to find journal articles which include statistics.