The average likelihood of an American being killed in a terrorist attack in which any kind of immigrant participated in any given year is one in 3.6 million - including the 9/11 deaths.
Research conducted by Cato Institute analyst Alex Nowrasteh examined data on terrorism and immigration from nine different sources, covering 1975 through 2015. He counted any attack in the US in which an immigrant participated as a terrorist attack by immigrants.
"Of the 3,252,493 refugees admitted from 1975 to the end of 2015, 20 were terrorists, which amounted to 0.00062 percent of the total," Nowrasteh writes. "Of the 20, only three were successful in their attacks, killing a total of three people."
American journalist Zack Beauchamp took it further by comparing the rate of death from other unusual incidents including the average annual likelihood of American pedestrians being hit by a railway vehicle and dying due to their own clothes melting or lighting on fire.
Breaking down the figures
The annual average of people dying as a result of being hit by a train in America is 5.81 per million. Deaths as a result of clothes melting or igniting are put at 3.33 per million annually. Deaths caused by immigrant-linked terrorism stand at 2.78 per million.
The table can be viewed in full here.
'New measures to keep radical Islamic terrorists out'
President Donald Trump signed an executive order Friday that indefinitely suspends admissions for Syrian refugees and limits the flow of other refugees into the United States by instituting what the President has called "extreme vetting" of immigrants.