Originally Posted by
Uncle Wurmy
The last 4 digits are consecutively assigned. So if someone got their SSN earlier (i.e. they are older), their number will likely be lower, and therefore more senior. Obviously this also depends on location which makes up part of the other numbers.
There are approximately 11,000 births per day in the United States. The last 4 digits of a Social Security number represents basically 10,000 numbers.