The original scheme implemented in 1936 by the Social Security Administration to assign an individual unique identification number was based on nine numerals divided into three segments:
o An "Area Number" assigned to a geographical area consisting of three numerals
o A "Group Number" consisting of two numerals issuable in an assigned Area o A "Serial Number consisting of four numerals and issued to one individual only.
The grouping appeared on the Social Security Identification Card in three blocks separated by hyphens, of the form AAA-GG-SSSS This system was in effect at least until 1972. I suppose there will come a time when all possible unique nine-digit unique numbers are in current use, so the fields will have to be expanded to provide more numbers. But right now I think the 9-digit system is sufficient.
There has never been an eight-numeral SSN, AFIK.
You have never seen an SSN that was either more or less than nine numerals, eh?
Yes. I had a brain fart.