In 2007, the busiest district courts in terms of criminal federal felony filings were the District of New Mexico, Western District of Texas, Southern District of Texas, and the District of Arizona. These four districts all share the border with Mexico. A crackdown on illegal immigration resulted in 75 percent of the criminal cases filed in the 94 district courts in 2007 being filed in these four districts and the other district that borders Mexico, the Southern District of California. The busiest patent litigation court is the United States District Court for the Eastern District of Texas, with the most patent lawsuits filed there nearly every year.