Steven A. Camarota, MA, PhD, Director of Research at the Center for Immigration Studies (CIS), in the Aug. 2004 CIS report "The High Cost of Cheap Labor: Illegal Immigration and the Federal Budget," wrote:

“When defense spending is not considered, illegal households are estimated to impose costs on the federal treasury of $6,949 a year or 58 percent of what other households received. When defense spending is included, their costs are only 46 percent those of other households. However, they pay only 28 percent as much in taxes as non-illegal households. As a result, the estimated net cost per illegal household was $2,736. Whether one sees this fiscal deficit as resulting from low tax payments or heavy use of services is a matter of perspective. As already discussed, illegal households comprise 3.6 percent of the total population, but…they account for an estimated 0.9 percent of taxes paid and 1.4 percent of costs.”

Aug. 2004