An exhaustive new report on the nation's top 472 occupations finds that immigrants -- legal or not -- take some jobs from Americans, dispelling the accepted view that foreign workers only fill jobs Americans don't want to do.

The study based on U.S. census data from 2009 to 2011 found that of the 472 jobs, immigrant workers outnumber "native-born" Americans in only six occupations: sewing machine operator, agriculture, masonry, plasterer, fruit and vegetable sorter, and tailor.

The group found no occupation where illegal immigrants dominated. In fact, many jobs assumed to be majority immigrant aren't. For example, 51 percent of maids are American-born, 64 percent of landscapers are American and 66 percent of construction laborers are natives.

"There are really no jobs that Americans won't do," said the authoritative report from the nonpartisan Center for Immigration Studies. The report is titled "Are there really jobs Americans won't do?" and was written by the center's Steven Camarota and Karen Zeigler.

The group said it would be a "mistake" to believe that every immigrant takes a job from a native-born American. But their report, provided to Secrets, said "it would also be a mistake to assume that dramatically increasing the number of workers in these occupations as a result of immigration policy has no impact on the employment prospects or wages of natives."

The report also suggested that immigrants taking American jobs affects unemployment rates. Noting that nearly 40 million Americans are out of the labor force, the report said, "it is very possible that one of the ways immigration impacts natives is by reducing the share who are employed or in the labor force at one time."

The report could have an impact on the debate over immigration reform, which President Obama has taken to Mexico to sell this week.

It piggybacks on another detailed analysis that projects legal and illegal immigration from Mexico is expected to increase slightly to 260,000 a year over the next five years. But the Migration Policy Institute said that it won't reach its Clinton era heyday of 466,000 because of increased border enforcement, an improved economy in Mexico and a lack of low-skill jobs in the United States because of the foundering recovery.