The number of patent litigation cases filed peaked in 2004 with just over 3000 cases. Filings have since dropped slightly in 2005 to approximately 2700, yet rebounded in 2006 to approximately 2800.
 
If those number interest you… then aside from probably being an attorney or having been involved in a patent infringement lawsuit… you may like to know where most patent litigation cases have recently been filed (i.e. which district courts see the most patent litigation).

2006 Rank     2005 Rank       District      # of 2006 Filings     % of National Total
    
1                          1                   CD Cal                    262                            9.63
2                          6                   ED TX                     216                            7.94
3                          2                   ND Cal                   195                             7.17
4                          7                   DNJ                        143                             5.26
5                          3                   ND Ill                      132                             4.85
6                          4                   SDNY                      121                             4.45
7                          5                   D Del                      120                             4.41
8                          11                 D Mass                   76                               2.79
9                          13                 ND Ga                     73                              2.66
10                         9                  D Minn                    66                              2.43
11                       14                 SD FL                       62                              2.28
12                         8                 ED Mich                   61                               2.24
13                       16                 ND TX                       54                              1.99
14                       15                 SD Cal                    52                                1.91
15                       12                 MD FL                       50                              1.84
16                       20                 D Colo                       48                             1.76
17                       22                 D Utah                       45                             1.65
18                       10                 ED Pa                       44                               1.62
19                       24                 ND Ohio                   41                                1.51
20                       na                 D Ore                       40                                1.47
21                       na                 ED Wis                      40                               1.47
22                       na                 D Conn                    39                                1.43
23                       na                 ED Mo                       39                               1.43
24                       21                 EDNY                       37                                 1.36
25                       19                 ED Va                       35                                1.29

* SOURCE: ADMIN. OFFC. of U.S. COURTS ANNUAL RPTS.

David Dawsey – Keeping an Eye on Patent Litigation in the Golf Industry

Other patent litigation posts that you may enjoy:

a) The True Cost of Patent Litigation 

b) Top 10 Intellectual Property Verdicts of 2006 - The Awards are Staggering 

c) Intellectual Property Infringement Statistics; Filings, Trials, and Awards 

d) Patent Infringement / Patent Litigation: What Is It and How Does It Work?