For more than 20 years, the Dartmouth Atlas Project has documented glaring variations in how medical resources are distributed and used in the United States. The project uses Medicare and Medicaid data to provide information and analysis about national, regional, and local markets, as well as hospitals and their affiliated physicians.
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.