<P> As of 2003 created the NUIP (Número Único de Identificación Personal), starting the numbering per billion (1,000,000,000). </P> <P> In Mexico, the ID number is called the CURP (Clave Única de Registro de Población) although the most important and accepted ID card would be the election card ("credencial de elector" or else "credencial del INE," as per the initials of "Instituto Nacional Electoral / National Institute of Elections, the institution responsible for electoral procedures). There are, however, other important ID numbers in Mexico: for instance, the social security number, which is the number assigned by Instituto Mexicano del Seguro Social (Mexican Institute of Social Security, or IMSS) to every citizen who starts working, or the RFC (Registro Federal del Contribuyente) which is assigned by the Treasury and has the same format as the CURP but a shorter length . </P> <P> In the United States, a Selective Service Number must be applied for by all male citizens turning age 18 . An optional national identity number is the Social Security number (SSN), a nine - digit number issued to U.S. citizens, permanent residents, and temporary (working) residents . Its purpose was to identify individuals for the purposes of Social Security, but it is now also used to track individuals for taxation purposes . There is no legal requirement to have a SSN if it is not required for Social Security or taxation purposes, but in practice one is required for many other purposes, for example to open a bank account or apply for a driving license, so that nearly all U.S. citizens and permanent residents have one . The SSN has therefore become a de facto national identification number, despite the fact that originally it was expressly not for this purpose . In fact, a valid SSN can be easily guessed, as they were issued serially prior to June 25, 2011 . </P> <P> In Venezuela, the Administrative Service of Identification, Migration, and Immigration (SAIME) issues an ID card for individuals in their teens (Cédula de Identidad). The ID card includes date of birth, a correlative number (population continuous number for nationals, greater than 80,000,000 for foreign - born residents), a photo, marital status, expiration date (an expired ID card is still valid for nationals), and a fingerprint . Newly issued ID cards are valid for 10 years . </P>

How many digits is a social security number