"There are several existing databases that describe the incidence of terrorist activity. Perhaps the most well-known of these is the International Terrorism: Attributes of Terrorist Events (ITERATE) database. These data were originally compiled by Mickolus (1982) and spanned a period from 1968 to 1977. They were later by Mickolus et. al. (1989, 1993) and Mickolus and Flemming (2003) until they now extend to 2002. Included in these data are the date of attack, the type of event, the number of casualties (deaths or injuries), as well as various other characteristics of incidents. There are roughly 12,000 incidents reported in the ITERATE database, spanning a 24-year period from 1968 to 2001. Importantly, however, only transnational terrorist events are considered. ITERATE defines an event as transnational along several criteria. These include the nationalities of the perpetrators, the location of the attack, as well as the nature of the target."