In addition, people from the countries in Trump’s crosshairs have certainly committed acts of terrorism in the United States; a Somali refugee injured several people in an attack at Ohio State University just this fall. Asylum-seekers have also recently been implicated in terrorist plots in Europe.

But after sifting through databases, media reports, court documents, and other sources, Alex Nowrasteh, an immigration expert at the libertarian Cato Institute, has arrived at a striking finding: Nationals of the seven countries singled out by Trump have killed zero people in terrorist attacks on U.S. soil between 1975 and 2015.

Zero.

Six Iranians, six Sudanese, two Somalis, two Iraqis, and one Yemeni have been convicted of attempting or executing terrorist attacks on U.S. soil during that time period, according to Nowrasteh’s research. (Nowrasteh focused on plots against the U.S. homeland, which presumably Trump cares most about, rather than other terrorism-related offenses, like supporting a foreign terrorist group or trying to join a jihadist organization overseas.) Zero Libyans and zero Syrians have been convicted of doing the same. “Foreign-born terrorism is a hazard,” Nowrasteh argues, “but it is manageable given the huge economic benefits of immigration and the small costs of terrorism.”

As for refugees, Nowrasteh writes, Trump’s action “is a response to a phantom menace.” Over the last four decades, 20 out of 3.25 million refugees welcomed to the United States have been convicted of attempting or committing terrorism on U.S. soil, and only three Americans have been killed in attacks committed by refugees—all by Cuban refugees in the 1970s.

Zero Americans have been killed by Syrian refugees in a terrorist attack in the United States.

Between 1975 and 2015, the “annual chance of being murdered by somebody other than a foreign-born terrorist was 252.9 times greater than the chance of dying in a terrorist attack committed by a foreign-born terrorist,” according to Nowrasteh.

Nowrasteh has listed foreign-born individuals who committed or were convicted of attempting to commit a terrorist attack on U.S. soil by their country of origin and the number of people they killed. As in any exercise like this, the statistics are rough and directional rather than precise. For example, the San Bernardino attacker Tashfeen Malik, who was born in Pakistan but lived in Saudi Arabia most of her life, is counted as originating from Saudi Arabia. In the case of attacks perpetrated by multiple terrorists, like 9/11, each terrorist is assigned an equal number of victims.

Still, it’s worth noting that the countries at the top of the list, including Saudi Arabia and Egypt, are not included in Trump’s ban. I’ve bolded the countries included in Trump’s executive order.

The 9/11 attacks were carried out by 19 men—from Saudi Arabia (15), the United Arab Emirates (2), Egypt (1), and Lebanon (1). The incident remains influential in how Americans think about the nature of terrorism; Trump’s executive order cites 9/11 as a prime example of the U.S. visa process catastrophically breaking down. But it’s misleading as a guide to where today’s terrorists come from.