If you want the most accurate representation of your coverage area you will need to do local processing. There is a tremendous about of processing FlightAware does to generate the ADSB stats page for 9000+ sites. If you need more accurate representation of the data than on your ADSB stats page you will need parse this yourself.
The local data feed can be grabbed by dump1090 that can then be parsed and counted by a program.
There is a forum post about how to do parsing and some parsing programs people have built below:
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I have looked at some of the parses people have put up and they are very similar to what is on the ADSB stats page. The main difference is that some planes are counted in the previous hour or the next hour. Or that some distance bins are counting the plane in a closer or father bin. The total counts in a day matches up closely between what FlightAware is showing and what people are parsing.
Also, the ADSB team is putting out a monthly newsletter. We will be including information about ADSB and what people are doing with ADSB. Parsing the local feed is definitely something people are interested in and we will probably do an article on it.