I'd be very interested to see a breakdown of the number of applications for every day in July (as measured by mailing date), because I suspect the highest counts would in the last week (7/24 through 7/28). I sent my package in on 7/24 and my number is SSC*00138**** (my wife's number is +2). Bobsmyth sent in his package on 7/28 and I seem to remember him posting his number as SSC*0014*****. If the number after the 4 is a 0, then my number is of the order of magnitude of 20,000 lower than his (because the number after my 8 is low). I don't know if these numbers count ALL applications to USCIS, or just N400 applications, but it does suggest that the July spike was pretty severe in that last week!
A good place to start is to look at the receipt graph on the USCIS website where you can see how they were close to 130000 for July and 135000 for June.
http://www.uscis.gov/files/article/N-400%20NATURALIZATION%20BENEFITS_June07.pdf