It looks like you're using Internet Explorer 11 or older. This website works best with modern browsers such as the latest versions of Chrome, Firefox, Safari, and Edge. If you continue with this browser, you may see unexpected results.
Source: Smith, et al., "Conducting high-value secondary dataset analysis: An introductory guide and resources", Journal of General Internal Medicine, 26(8):920-9, August 2011
National Library of Medicine Health Statistics course
Interested in learning more about how to find and use health statistics? The National Library of Medicine provides a free comprehensive online course.