when you go to the FBI website, it will tell you what the current processing time is. Currently, it's 32 days, not including mail. The time seems to be increasing slightly over the summer. The processing time changes seasonally. Below is the link for how to request your document.
http://www.fbi.gov/about-us/cjis/identity-history-summary-checks
EDIT: remember CIC only considers the record valid for 3 months, so it's important to coordinate mailing the package with getting the record back.