President Trump’s updated travel order could result in Muslim immigration to the United States being reduced by as much as 21 percent, based on Department of Homeland Security statistics from 2015.

Trump’s travel order announced Sunday would block all permanent immigration from seven countries: Iran, Libya, North Korea, Syria, Somalia, Yemen, and Chad. In addition, non-immigration temporary visas are restricted for some Venezuelan government officials.

During Trump's campaign, he once called for a "total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what is going on."

Trump later backed off that, and his new order never mentions religion; instead it describes in detail how the list was compiled based on non-religious security factors.

But in impact, five of the seven blocked countries -- Iran, Libya, Syria, Somalia, and Yemen -- are overwhelmingly Muslim.

It is impossible to say exactly how many fewer Muslims would be allowed to immigrate in the future due to the order, but the past data from 2015 likely serve as a good estimate, as immigration figures have been relatively stable. In 2014, 126,742 people came from the Islamic world; in 2015, it was a similar 131,061.

In 2015, the United States gave permanent immigration visas to 27,678 people born in those countries, according to the latest data from the Department of Homeland security.

If those 27,678 people had not been allowed to immigrate in 2015, that would have stopped 21 percent of immigration from the Islamic world that year -- out of a total of 131,061 people who were admitted from countries in which the large majority - more than two-thirds - are Muslim.

The Department of Homeland Security does not include immigrants' religion in its statistics, so the 21 percent figure is an estimate based on the main religion in the countries from which people came.

The new order marks a change from the original travel ban in that it focuses most on restricting permanent immigration rather than temporary travel, noting that, “permanent residents are more difficult to remove than nonimmigrants even after national security concerns arise.”

Refugees are processed separately by the government, and are not impacted by this executive order or included in the numbers above. But the impact of Trump's policies on refugee admissions has been even more stark; nearly 3,000 Muslims were admitted as refugees in January, but that fell by more than 90 percent, to just under 250 admitted, in August.

Trump's order still allows continued immigration from several major Muslim countries with a lot of immigration to the U.S., such as Pakistan (18,057 immigrants in 2015), Egypt (12,085), and Afghanistan (8,328).

Trump immigration critics say his latest ban is wrong and isn’t even applied to the countries with the biggest terror problems.

“No person from any of these countries has killed any American in a terrorist attack on U.S. soil in at least the last four decades,” David Bier, immigration analyst at the libertarian CATO Institute, told FoxNews.com.

Some of the most deadly recent terror incidents were by people from countries that are not being blocked – the San Bernardino shooters who killed 14 people last were from Pakistan. The Orlando Nightclub shooter who murdered 49 people was the son of an Afghani immigrant who was a Taliban supporter.

Bier, however, says that’s not a reason to just extend the ban to other countries.

“The risk of terrorism by foreigners in general is already miniscule,” he said, adding that in any given year the average American has only a 1-in-3.6 million chance of being killed in a terror attack.

“The economic costs of the new ban already far outweigh the supposed benefits,” he said, adding that “national origin is not a good predictor of terrorist activity.”

Mark Krikorian, who runs the Center for Immigration Studies, supports restrictions.

“The fact is, the danger is coming from Islamic groups. There are no Buddhist terror groups bombing people in United States,” he said.

But he also noted that order clearly does not amount to “Muslim ban” considering that non-Muslim countries are also on the list and the list was compiled based on whether countries complied with vetting.

The new order, he said, shouldn’t even be controversial.

“Trump’s initial order wasn't a ‘Muslim ban’, and this isn’t a ‘Muslim ban.’ It’s so prosaic. Banal, even. This is just the daily work of homeland security.”

Maxim Lott can be reached on twitter at @maximlott