Haven't checked the STF site in awhile, so took a peek:

Data Collection Period Banned Accounts Frozen Gil
12/1/2009 - 12/31/2009 13,729 Approx. 400 million
11/1/2009 - 11/30/2009 17,180 Approx. 700 million
10/1/2009 - 10/31/2009 14,080 Approx. 1.0 billion
9/1/2009 - 9/30/2009 14,140 Approx. 900 million
8/1/2009 - 8/31/2009 13,370 Approx. 1.5 billion
7/1/2009 - 7/31/2009 31,630 Approx. 2.7 billion
6/1/2009 - 6/30/2009 16,230 Approx. 2.1 billion
5/1/2009 - 5/31/2009 12,170 Approx. 2.7 billion
4/1/2009 - 4/30/2009 9,500 Approx. 2.3 billion
3/1/2009 - 3/31/2009 11,070 Approx. 1.5 billion
1/28/2009 - 2/28/2009 7,650 Approx. 2.1 billion
12/23/2008 - 1/27/2009 7,210 Approx. 1.5 billion


That July number works out to about 988 accounts per server.