ISIS, Boko Haram, Al-Qaeda, Taliban Increase Deaths Terrorism-Related Deaths Up 60% Last Year, Study Says An Afghan policeman is seen through the wreckage of a taxi which was destroyed by a suicide attack targeting a vehicle convoy of Afghan lawmakers in Kabul, Afghanistan on Nov. 16, 2014. Farshad Usyan - AFP/Getty Images More than 80% of the deaths occurred in Afghanistan, Iraq, Nigeria, Pakistan and Syria Nearly 18,000 people were killed in terrorist-related incidents last year, a 60% increase from the previous year, a new study found. Deaths have increased five-fold since 2000. The report, compiled by the Institute for Economics & Peace, attributes the increased terrorist activity to the growing influence of "radical Islamic groups." Two thirds of the fatalities came at the hands of ISIS, Boko Haram, al-Qaeda and the Taliban, the report said. "Given the theological nature of the problem it is difficult for outside actors to be influential," Steve Killelea, institute executive chairman, said in a statement. As the number of deaths has expanded, the location of attacks has remained limited. More than 80% of the deaths occurred in just five countries: Afghanistan, Iraq, Nigeria, Pakistan and Syria.