More Than 36 Million People
Nguyễn (阮) is the most common Vietnamese family name. By some estimates, approximately 40 percent of Vietnamese have this surname. The prevalence of Nguyễn as a family name in Vietnam extends to outside of the country where many Vietnamese have emigrated. Nguyễn is the 7th most common family name in Australia, and the 54th most common in France. In the United States, it is the 57th most common family name according to the 2000 Census, as well as the most common exclusively Asian surname.
http://www.theworldgeography.com/2012/02/10-of-most-common-surnames-in-world.html
Nguyễn (阮) is the most common Vietnamese family name. By some estimates, approximately 40 percent of Vietnamese have this surname. The prevalence of Nguyễn as a family name in Vietnam extends to outside of the country where many Vietnamese have emigrated. Nguyễn is the 7th most common family name in Australia, and the 54th most common in France. In the United States, it is the 57th most common family name according to the 2000 Census, as well as the most common exclusively Asian surname.
http://www.theworldgeography.com/2012/02/10-of-most-common-surnames-in-world.html