These two digits means in

来源: 于 2005-10-19 10:24:30 [旧帖] [给我悄悄话] 本文已被阅读：次

what fiscal year (Oct 1 through Sept. 30) did the USCIS receive your case. Mine was assigned to 2006. But my received date is 9/29/05.

Thanks for sharing the information!