A good place to start is with the US Government, which collects a large amount of health data. Agency websites serve as portals to finding health statistics on all kinds of topics, so they make a great starting place in your search for statistical information.
The CDC is a part of the U.S. Department of Health & Human Services and is the primary federal agency for public health.
Data and Statistics: This is the starting point for health statistics from the CDC. Browse by topic, view publications, and links to interactive tools, surveys and more.
Health Data Interactive: Customizable tables for national health statistics covering topics in health status, health care, conditions, insurance, mortality, life expectancy, birth, pregnancy, risk factors and disease prevention.
CDC Wonder:A portal to several CDC databases concerning health-related topics for public health information and numerical data sets such as AIDS/STDs, risk behaviors (the Behavioral Risk Surveillance System), mortality and natality statistics.
The NCHS is the nation's principal health statistics agency. It is a unit of the CDC. The NCHS homepage is also a central point for health statistics browseable by topic, links to surveys, publications, and other online tools.
Sponsored by the National Library of Medicine, this organization is a portal of health services research resources that provide numerous links to data, funding announcements, reports, podcasts, discussion groups, and more.