Terrorism and the Olympics by-the-numbers

The Olympic Games have been terror targets on three separate occasions since 1970, claiming 22 lives and wounding more than 100, the report says. It compiles and analyzes data from START's comprehensive Global Terrorism Database (GTD).

"The heightened profile of these events might increase the likelihood of a terrorist attack while the heightened security and surveillance might decrease the likelihood of an attack," explains START researchers and report co-author Erin Miller.

The analysis revealed no consistent increase or decrease in the frequency of terrorist attacks during the Olympics when compared with other time periods in the same city, which suggests that considerable efforts to reinforce security are generally effective at mitigating any potential threats, Miller adds.

The background report details the fatal attacks that occurred in three Olympic host cities: Munich (1972), Atlanta (1996) and Beijing (2008).

Host Countries:The background report further examines the patterns of terrorism in 20 Olympic host countries in the year prior to the start of the games as compared to the time of the games. Of the 15 countries that saw terrorist attacks during these time periods:

• More attacks during Olympics than in the prior year: nine;
• Fewer attacks during Olympics than in the prior year: six;
• Fewer fatalities during Olympics than in prior year: three;
• More fatalities during Olympics than in the prior year: six.

London and UK Terror: The background report also reviews the history of terrorism in London and the United Kingdom. Since 1970, there have been 380 attacks in London causing more than 175 fatalities and more than 2,200 injuries.

The researchers note that these attacks were infrequent with the most recent being a series of four coordinated suicide bombings on public transportation. The attack, claimed by a group calling itself "Secret Organization of al Qaida in Europe," killed 56 and wounded more than 700.