(Source: U.S. Census Bureau)
That divide in incomes also is reflected in poverty data. In 2011, around 14.4 percent of native-born Americans were below the poverty line. That's just higher than 12.5 percent for naturalized immigrants, but it's also well below the 24.3 percent poverty rate for non-citizens.
This divide between naturalized and non-naturalized immigrants is due to a variety of factors. One is the direct tie between citizenship status and wages, says Walter Ewing, senior researcher at the Immigration Policy Center, the research arm of the American Immigration Council, which promotes immigration. He points out that citizens are less subject to exploitation and are eligible for far more jobs, like many in the public sector.
However, indirect factors also come into play, says Ewing.
"If you're applying for U.S. citizenship, chances are that you have superior English skills, you've been in the country longer," he says.
Speaking better English and being more assimilated into American culture may simply be more attractive to employers, he adds. "It's not that all of that wage gain is caused by getting citizenship. Some of it is, but not all of it."
The Economy Needs More Well-Educated Immigrants
Another potential component of immigration reform is a change to the cap on worker visas. There is already a bill in the senate aimed at doubling the number of H-1B visas—the kind of visas that are given to high-skilled foreign workers—issued each year. Demand for these visas shifts from year to year, but since the cap has been set at 65,000, the number issued has regularly been exhausted well before the end of the year.
(Source: Government Accountability Office)
Some experts say that a change in this cap is a long time in coming.
"There's a very, very high demand for these H-1B visas," says Lauren Crawford, a partner at Hamilton Place Strategies, a policy and communications consulting firm in Washington, D.C. "How do we devise a system and allow caps to be flexible year to year, so we can meet the demand of our businesses for people that want to apply to come here and do it? Right now our situation is very static and has no correlation whatsoever to what is going on in the economy."