This is the tenth one so far, there's one more on the 22nd, then four in December, then six in January, then one in February and two in March. And those are just the ones scheduled currently.
For comparison in 2008:
Democrats had 26 total debates, about 13 by this point. Six of the total were just Clinton and Obama, with three more with just Edwards added.
Republicans had 21 total debates, 12 by this point. None after February 2nd. McCain and Romney's last one was Jan 30.
In 2004, the Democrats had 16 total debates, 7 by this point.