This site offers a variety of material. Besides extensive information for beneficiaries, there is substantial statistical material, basically annual and current operating tables. Since these tables are in different formats, be sure to read the appropriate descriptions of them. For ftp access, see the file "pub/statistics/README.FIRST". For gopher access, in the "K-Statistical Data and Abstracts" directory, read the file "A-ORS Master Index (Please Read First)".
http://www.ssa.gov/
gopher://gopher.ssa.gov
ftp://ftp.ssa.gov