Dominique Strauss-Kahn’s accuser, Nafissatou Diallo, met with prosecutors Wednesday for the first time since the district attorney’s office raised doubts about her credibility. The Guinean immigrant and hotel maid shares a surname with several other notable Guineans, including Amadou Diallo, an unarmed 23-year-old immigrant who was shot and killed by four plain-clothed police officers in 1999, and Cellou Dalein Diallo, an economist who was prime minister of Guinea from 2004 to 2006. Is Diallo the Smith of West Africa?

Yes, and then some. The name is everywhere in Guinea—applying to roughly 10 percent of the population, experts say—and fairly common across the rest of West Africa, too. For comparison, there were just 2.4 million Smiths in the United States as of 2000, accounting for just 0.9 percent of the population. (Johnsons came in second place, with 1.9 million, or about 0.6 percent.)

What makes Diallo so common? A significant portion of the Guinean population is Fulbe, or Fulani, and almost all Fulbe have one of four family names: Diallo, also spelled Jalloh; Barry; Balde, also spelled Bah; and Sow. (Diallo is not any more popular than the other three names.) About two-fifths of all Guineans are Fulbe, and they live in smaller concentrations in other countries throughout West Africa, with significant clusters in Senegal and Mali, where many more Diallos are found.

Vietnam may be the country where a single surname is most dominant. About 40 percent of the people there have the family name Nguyen. Many Vietnamese have surnames that come from one of the royal families that have ruled the country; the Nguyen Dynasty happens to be the last.

Got a question about today’s news? Ask the Explainer.

Explainer—whose surname is the 69th most common in the United States—thanks Robert Bernstein of the U.S. Census Bureau, Grace Dobush of Family Tree Magazine, Patrick Hanks of the Family Names Research Project at the University of the West of England, Mike McGovern of Yale University, Frank Nuessel of the University of Louisville, and Kemp Williams of the American Name Society.