Between 1970 and 2011, there have been 2,608 total attacks of terror in the United States, and 226 fatal attacks. The odds of an American being killed in a terrorist attack - including both domestic attacks and those overseas - have been about 1 in 20 million in the past five years. In fact, the number of terrorist attacks on American soil has declind steadily since the 1970s, and in the decade between 2001 and 2011, there was a particularly low number of attacks and deaths. See the resources below for more info on the history of terrorist attacks in the U.S., as well as current counter-terrorism efforts.
History and Figures
A timeline of terrorist attacks against the United States and Americans since 1920.
Terror Trends: 40 Years' Data on International and Domestic Terrorism
This 2011 report from The Heritage Foundation aggregates international data on global and domestic terrorism from the past 40 years. It notes that between 1969 and 2009, there were 38,345 terrorist incidents around the world, and of these attacks, 7.8 percent - or 2,981 - were directed against the U.S. The report also notes that law enforcement has foiled at least 39 terror plots against the U.S. since September 11.
Global Terrorism Database
Hugely useful open-source database that includes information on terrorist events around the world from 1970 through 2011. The resource contains information on more than 104,000 terrorist attacks. It is maintained by a consortium of researchers and based at the University of Maryland.
National Counterterrorism Center
The National Counterterrorism Center was established in August 2004 and provides information on known terrorist groups, individual terrorists, and technical information on topics such as biological and chemical threats. See this link on how to report any suspected criminal or terrorist activity.
Resources from the Department of Homeland Security. Includes info on public awareness programs and the National Terrorism Advisory System. It also offers the latest news.