JohnK 8/22/2013 8:23:45 PM
These would be the current processing statistics.
http://blog.mygcvisa.com/2013/08/uscis-eb-i-485-i-140-processing.html
In link above, it means there are 22,090 cases pending at NSC for I-485 application as of June 30, 2013. Starting time would be probably since they started releasing the data.
You can look at the previous statistics page to see how many applications were processed by USCIS in the last one month.