FOR SINGLE DATA YEARS: Death rates are calculated based on the resident population of the United States for the data year involved. For census years (e.g. 2010), population counts enumerated as of April 1 are used. For all other years, populations estimates as of July 1 are used. Postcensal population estimates are used in rate calculations for years after a census year and match the data year vintage (e.g. July 1, 2011 resident population estimates from Vintage 2011 are used as the denominator for 2011 rates). Intercensal population estimates are used in rate calculations for the years between censuses (e.g. 1991-1999, 2001-2009). Race-specific population estimates for 1991 and later use bridged-race categories.
In 2013, rates for 2007–2009 were revised using intercensal population estimates based on the 2000 and 2010 censuses instead of the postcensal estimates for the denominator. Thus, the original baseline was revised from 61.9 to 60.3. The target was adjusted from 55.7 to 54.3 to reflect the revised baseline using the original target-setting method.