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 95 means there are 95 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).
In 2013, the male-to-female sex ratio among the native-born population was 97 males to 100 females.
Migration Policy Institute tabulations of the U.S. Census Bureau's 2013 and 2010 American Community Surveys and 1970, 1990, and 2000 Census data accessed from Steven Ruggles, J. Trent Alexander, Katie Genadek, Ronald Goeken, Matthew B. Schroeder, and Matthew Sobek, Integrated Public Use Microdata Series: Version 5.0 [Machine-readable database] (Minneapolis: University of Minnesota, 2010). All other data are from Gibson, Campbell and Emily Lennon, "Historical Census Statistics on the Foreign-Born Population of the United States: 1850 to 1990" (Working Paper No. 29, U.S. Census Bureau, Washington, DC. 1999). This report is available online.