In order to bring a spouse into the United States, Form I-130 must be filed, which is an immigrant petition on behalf of a relative. After that, a K-3/K-4 & V-1/V-2 Entry Visa for Spouse must be filed. The Immigration and Nationalization Service advises that "in some cases, it may be to a couple's advantage to pursue a K-1 fiancee visa before getting married. In other cases, applicants may find that it is more cost effective to get married abroad and then apply for an immigrant visa overseas. In many cases, the K-1 visa application process takes just as long as the immigrant visa process". The cost of the visa may be around $2000. Couples must remain together at least two years. There were 849,000 female naturalized citizens between the ages of 20 and 29 and 2,084,000 women of the same age living without U.S. citizenship in 2016, accounting for 13.3% of the female population of that age bracket. "Despite well over 2,000 mail-order marriages a year, there is no information on the amount of mail-order brides entering the United States. The purpose of this law is two-fold: to protect the safety of mail-order brides and to prevent fraud".