One method used by demographers to measure the relative number of males and females in a population is the sex ratio. The male-to-female sex ratio is calculated by dividing the number of males (of all ages) by the number of females (of all ages) and multiplying by 100. A value above 100 means there are more males than females in the population. For example, a sex ratio of 117 means there are 117 males to every 100 females. A value below 100 indicates more females than males. A sex ratio of 84 means there are 84 males to every 100 females. A sex ratio of 100 means there are an equal number of males and females (i.e., 100 males to 100 females).
Source: The 2011 data are from the US Census Bureau's 2011 American Community Survey. The 2000 data are from the Current Population Survey, March Supplement, 2000. All other data are from Gibson, Campbell and Emily Lennon, US Census Bureau, Working Paper No. 29, Historical Census Statistics on the Foreign-Born Population of the United States: 1850 to 1990, US Government Printing Office, Washington, DC. 1999. This report is available online.