The average annuity for retired Members, as of 1998, was either $50,616 [for those that retired under CSRS] or $46,908 [for Members that retired under FERS]. However, these averages don't take into account any additional funds these Members may have also accrued through investments in the Thrift Savings Plan described above.
http://www.c-span.org/questions/weekly68.htm
What really gets my goat is that immigrants who come here ready for retirement get all the benefits without putting a penny into the system.