How many combinations are used with social security numbers?

Answer 1

Social Security Numbers (SSNs) are nine-digits in length. The maximum number of combinations without exclusion is 109, or one billion. However, a number of number combinations are excluded (e.g., 666-xx-xxxx, 000-xx-xxxx, xxx-00-xxxx, xxx-xx-0000, as well as SSNs beginning with most numbers over 733). After excluded combinations are taken into account, the maximum number of combinations is approximately 745 million. According to the Social Security Administration, approximately 442 million SSNs have been assigned, with 5.5 million new numbers assigned each year. At this rate, new numbers can be assigned over the next 52 years (i.e., 2009 through 2061) before reassigning numbers or changing the archetype. Sources: * http://ssa-custhelp.ssa.gov/cgi-bin/ssa.cfg/php/enduser/std_adp.php?p_faqid=86&p_created=955483126&p_sid=CrOQahCj&p_accessibility=0&p_redirect=&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9MjAsMjAmcF9wcm9kcz0mcF9jYXRzPTE2LDU4JnBfcHY9JnBfY3Y9Mi41OCZwX3NlYXJjaF90eXBlPWFuc3dlcnMuc2VhcmNoX25sJnBfcGFnZT0x&p_li=&p_topview=1 * http://en.wikipedia.org/wiki/Social_security_number