Vietnamese-Born Population, by Age and Sex, for the United States: 2011
The age-sex pyramid of the foreign-born population from Vietnam has many of the same characteristics as the "diamond shape" population pyramid of the total foreign born. This includes the largest number of immigrants in the economically active ages of 20 to 54 and relatively smaller numbers under age 20 and over age 54. Unlike the high male-to-female ratios of the Mexican and Indian populations and the low male-to-female ratios of the Filipino and Chinese populations, the Vietnamese male-to-female ratio is 91, which suggests a more sex-balanced population.
There were about 1.26 million immigrants from Vietnam residing in the United States in 2011. Male-to-female ratio: 91.1.
US Census Bureau, American Community Survey, 2011.