Please see below latest FB (family based) statistics released by USCIS:
USCIS I-130 - Preference Category Processing Statistics as of 05/31/2013
|All Other Pending||5,094||10,893||21,106|
|Pending but adjudication deferred||376,175||127,200||508,840|
|Customer action waiting||3,210||4,081||7,293|
This table will help you understand why the I-130 processing time in CSC for F2A is around 18 months.
CSC = California Service Center
VSC = Vermont Service Center
USCIS FB I-485 Processing Statistics as of 05/31/2013
|Customer action waiting||590||494||35,667|
New receipts: USCIS have recently received application
Pending: USCIS have started processing application
Customer action waiting: USCIS is waiting for more document(s) from customer (RFE)
Preadjudicated: USCIS have finished processing the case but visa number is not available
Completed: USCIS have completed processing application
If you are planning to file I-130 or I-485 application, the table above will give you an idea of how many applicants are ahead of you.
Since USCIS goes by last receipt date, if you are going to file your I-485 (or just filed), you will be placed behind this queue. Exception is if application is preadjudicated then it would go by PD.
Note: USCIS also updated their processing time few days ago. Please see the link on right side of this page (under USCIS Links)