A new study on immigration underscores that immigration – legal and illegal – is adding 8.3 million people to the U.S. population every four years and that some of the fastest rates of migration are coming from countries hostile to American values of freedom and democracy.

For instance, the sending country with the largest percentage increase in immigrants living in the U.S. during the four years from 2010 to 2014 was Saudi Arabia, with a 93 percent increase, followed by Bangladesh at 37 percent and Iraq at 36 percent.

About one-fourth of the 42.4 million foreign-born people living in the United States are illegal immigrants – this amounts to roughly 10.5 million, according to the study by Center for Immigration Studies.

While many immigration hawks might dispute that number and say it's actually much higher, the facts don't bear it out, says Steven Camarota, director of research for CIS and co-author of the report with demographer Karen Zeigler.

TRENDING: Alan Dershowitz sues CNN to halt 'malicious' attacks on innocent people

"You can easily have a situation where 400,000 new people settle in the U.S. every year by overstaying their visas or sneaking across the border and that doesn’t mean you're adding to the overall illegal immigrant population," Camarota told WND.

Read the entire study and view all the charts at CIS.com.

Obama in November 2014 issued a series of executive orders that granted amnesty to about 5 million illegals, or nearly half of the estimated 10.5 million to 11 million now in the country. The federal courts have thus far blocked his actions as unconstitutional, and the Supreme Court, which deadlocked on the issue previously, ruled Monday that it will not re-hear the case.

Meanwhile, illegal-alien crime sprees continue to rock the country, including a series of M-13 gang-related killings on Long Island. The most recent case involved the murder of two teenage girls.

On Sept. 13, Nisa Mickens, 15, and her best friend, Kayla Cuevas, 16, were murdered, their battered bodies found near an elementary school in Brentwood on the island, the New York Times reports.

A week later and just two miles away, the remains of two more teenagers – Oscar Acosta, 19, and Miguel Garcia-Moran, 15 – were discovered in the woods near a hospital.

For nearly two decades, MS-13, an El Salvadoran gang, has been "terrorizing" the town, especially its young people, according to the Times report. Since 2009, its members have been accused of at least 14 murders.

So the problems of illegal immigration are not to be downplayed. But the problems of legal immigration are many times greater, according to the CIS study, which analyzed Census data.

"You could have half-a-million every year come illegally, and in that same year some go home, every year some will die, and some who were illegal become legal," Camarota said.

He said there are more than 100,000 illegals given legal status every year.

"They marry an American, they find employment with a company that gives them a visa, they win the visa lottery, or they get a 'cancellation of removal' order from a judge that essentially gives them asylum status," he said.

Ann Coulter's back, and she's never been better than in "Adios, America!: The Left's Plan to Turn our Country into a Third World Hellhole."

"Some get deported, and some go home voluntarily every year on their own. We can calculate death rates by age, and that's why the overall illegal population can be stable even if 400,000 come in every year," he added.

"You also have to remember that there are no illegal-immigrant births in the United States, because everybody born here is automatically a U.S. citizen," Camarota added. "Now you can bemoan that and say it's wrong, but for these purposes we can't add them into the illegal population. We can only add those coming from abroad."

Legal immigration has roughly four times the impact of illegal immigration, Camarota says.

"So the bottom line is, illegal immigration is dwarfed by legal immigration. The impact on our schools and on our welfare system is much bigger, and also the political impact."

When states do apportionment and redistricting, they draw the lines for seats in Congress and state legislatures based on total population, regardless of immigration status.

"There are at least three legal immigrants for every illegal immigrant," Camarota said. "And while the illegals do vote fraudulently, sometimes it's the legal immigrants who vote in much larger numbers and have the big political impact on our system."

Legal immigrants are also more dangerous in terms of their propensity to commit acts of Islamic terrorism, a lesson that should have been learned from the 9/11 attacks in which the hijackers were here largely on student and tourist visas.

Refugees connected to acts of terror

More recently, the stabbing attacks on a St. Could, Minnesota, mall that injured 10 and the pipe bombings in New York city that injured 29 were carried out by refugees, meaning they were legal immigrants. The Chattanooga shooting of five U.S. servicemen and the mass shooting in San Bernardino in 2015, as well as the attack on an Orlando gay nightclub in June 2016, were all carried out by second-generation Americans born to Muslims who legally migrated to the U.S.

The study also found some surprising facts on jobs.

"There really are no jobs Americans won't do," Camarota said. "Pretty much every job category is at least half American, even farms, because there are still a lot of family farms."

In the area of entrepreneurship, Camarota found that immigrants do start businesses, but overall their rates of employment versus self-employment are about the same as native-born Americans. "So entrepreneurship is not lacking among immigrants but nor is it a distinguishing characteristic."

Promoters of refugee resettlement use 'stupid' arguments not supported by data

This refutes one of the main arguments used by mayors trying to promote refugee resettlement and mass immigration in their cities.

"The way in which refugee resettlement gets sold sometimes is so stupid," Camarota said. "We could all say that the idea that they are fleeing for their life is probably not true in most cases, but the idea is that they are in desperate circumstances and we're taking them as a humanitarian gesture. But we know from lots of data that refugees use welfare in large amounts and for very long periods of time. We know that about this population, so it's reasonable for them to struggle financially.

"Resettlement, if we're going to do it, should be done as part of an honest discussion. We have the data on this, but we don't [have an honest discussion]."

Welfare usage rates extremely high

Rates of welfare usage are not only high among refugees but also among immigrants from Latin America.

"Sixty percent of families from Mexico use at least one welfare program," Camarota said. "Roughly half the Mexicans in the U.S. are illegal. But more importantly, what you see here if you pull out the illegals from Mexico and Latin America and you see that they sign their kids up for lots of programs. And those kids were born here, many of them. Even if they were not born here and are illegal, they can get free school, WIC and Medicaid. A pregnant woman can get Medicaid too if she is illegal."

This is something that was not a problem during earlier waves of immigration in the 1880s, 1920s and 1950s. Immigrants were required to be self-supporting.

"Lots of immigrants come to America now and can't support their own kids," Camarota said. "They have to turn to the taxpayer. That's the question to ask. Depends how you feel about that."