Usama bin Laden led Al Qaeda to become the most lethal terror group in the world, according to a recent study.

The study, by the National Consortium for the Study of Terrorism and Responses to Terrorism (START) at the University of Maryland, said Al Qaeda was responsible for more than 10,000 deaths and injuries in 12 years. The terror group has killed more than 4,000 people since 1998, according to the report.

“Al Qaeda, the terrorist organization Usama bin Laden founded, was responsible for fomenting more mass casualty attacks than any other group in recent history,” said START Director Gary LaFree, a University of Maryland professor who has assembled the world’s most comprehensive unclassified terrorism database. The terror group has killed more than 4,000 people since 1998, according to the report.

The report shows that Al Qaeda was responsible for, or suspected to be responsible for, 84 terrorist attacks around the world since 1998, resulting in the deaths of at least 4,299 individuals. Another 6,300 people were wounded in Al Qaeda attacks.

The report concludes that Al Qaeda’s efforts were deadlier by far than those of most other known, long-term terrorist groups, including ETA, the Basque separatist organization in Spain, which killed 820 people between 1972 and 2008. IRA attacks have killed about 1,829 people dating back to 1970. The only group that comes close in terms of lethal attacks is the Revolutionary Armed Forces of Colombia (FARC), killing 4,835 people during the course of its existence.

Click for the full report, including a breakdown by year of Al Qaeda terror attacks and casualties.