Shadow workers: Hungry, hard-working - boon or bane?

"We'd have higher prices for agriculture, higher prices for lawn care, we'd have higher prices for a lot of things," Perlich said.

Like "Sarah," "Manuel" also has a low-paying job in Utah. He does construction, receiving $8 an hour helping two men work on their East bench houses.

"Maria" says she has a good boss. She gets $6.25 a hour working on a small Brigham City dairy farm.

A recent Deseret Morning News/KSL-TV poll conducted by Dan Jones and Associates found that nearly 60 percent of Utahns believe that undocumented immigrants hurt both the U.S. and Utah economies.

Slightly less than 30 percent believed illegal immigrants help the economy, according to the the poll of 413 people. The poll has a 5 percent margin of error.

It's easier to evaluate the impact of undocumented workers on the national economy.

• A report by the nonpartisan research organization Pew Hispanic Center estimates that an estimated 6.3 million unauthorized workers comprised only about 4.3 percent of the nation's work force in 2004.

• Only 10 percent of unauthorized workers are in management, business and professional occupations, compared to 35 percent of the U.S. workers, according to the Pew report. The highest concentration of unauthorized workers was 33 percent in the service occupations, compared to 15 percent of the U.S. population.

• The average undocumented person makes $12,000 a year, less than half the average income of an U.S.-born worker, and roughly 60 percent what the average legal immigrant makes, the Pew report found.

• Illegal immigrants comprise 20 percent to 25 percent of some construction occupations, Pew demographer Jeffrey Passel says. Some 26 percent of workers in landscaping are undocumented, as are one of every five workers in the meat/poultry industry, according to the Pew report.

• The illegal work force holds down wages for low-skilled, uneducated Americans. Harvard professor of economics and social policy George J. Borjas has done the math. Over the past 20 years, immigration (much of it illegal) increased the pool of workers without a high-school diploma by 16 percent.

"The typical high-school dropout earns $21,000 annually," he wrote. "Immigration lowers this worker's salary by around $1,300."

• The Social Security administration reports a total of 9 million W-2s in 2002 with incorrect Social Security numbers, which accounts for $56 billion in earnings.

• Illegal immigrants are also estimated to be contributing about $1.5 billion per year in Medicare taxes.

Under the radar