A new study finds that almost half of the alleged terrorists charged in the United States were inspired by jihadist groups other than the Islamic State in Iraq and Syria (ISIS).

“While an unprecedented number of Americans have radicalized in support of [ISIS] in the last five years, sustained terrorism arrests unrelated to [ISIS] indicate that other terrorist organizations within the global jihadist movement continue to appeal to Americans,” the study from the George Washington University's Program on Extremism said.

The terror group, which controls land in parts of Syria and Iraq, has directed attacks in Europe, specifically in Belgium and France.

The study’s research did not include suspects who have been killed by police in attacks, including the shooting in Garland, Texas at a “Draw the Prophet Muhammad” contest. The study also did not include Americans who have traveled abroad since 2011 to wage jihad.