Over his lifetime, the typical immigrant is a net contributor to public coffers, according to a new joint study by the Cato Institute and the National Immigration Forum.

The study, "A Fiscal Portrait of the Newest Americans," by economist Stephen Moore, confirms a 1997 study by the National Research Council which calculated that immigrant households pay between $20,000 and $80,000 more in lifetime taxes than they collect in lifetime services -- and perhaps more.

• After an average of 10 to 15 years in the U.S., non-citizens' earnings match and then exceed those of native-born Americans.

• Immigrant households with a naturalized citizen pay $6,580 a year in taxes -- compared to $5,080 for the average citizen.

• Each year's new immigrants arrive with $40 billion worth of education acquired in their native countries.

• Since just under half of all immigrants come to the U.S. as they begin their working years, they will pay $500 billion more into Social Security over the next 25 years than they will receive in benefits when they retire.

Moore says that over the next 75 years, they will pay close to $2 trillion more in Social Security taxes than they receive in benefits.