For almost 15 years, all of the net gain in jobs in the U.S. economy has gone to immigrants — legal and illegal — a new study has found.

The Center for Immigration Studies report says nearly 6 million more people are working in the United States since 2000, 5.7 million of which are immigrants. Put another way, the number of new jobs obtained by native-born people has declined slightly, from 114.8 million to 114.7 million."Some may think that immigrants and natives never compete for jobs. But a majority of workers in virtually every occupation are native-born. Immigrants have made gains across the labor market in lower-, middle-, and higher-skilled jobs," said Steven Camarota, research director for CIS and lead author of the report, according to The Washington Times Some of the native-born are unemployed, but many have become economically inactive, or are no longer looking for work, as a result of losing out to competition with immigrants, Camarota said."The idea that there are jobs Americans don't do is simply not supported by the data," Camarota and co-author Karen Zeigler wrote.Young native workers have been hit particularly hard and native-born minorities have also been disproportionately affected, the report found.The study could provide fodder to those opposed to arguments by business leaders that the United States should welcome an influx of workers through immigration reform — among them media magnate Rupert Murdoch and Facebook founder Mark Zuckerberg.The Senate immigration reform bill passed last June would provide a pathway to citizenship for the estimated 11.5 million undocumented immigrants while also increasing the number of legal workers, adding an estimated 9.6 million foreigners to the workforce, according to the Times.The Congressional Budget Office estimated the bill would boost the economy by 3.3 percent over 10 years, but that average wages would drop slightly in the first decade as workers compete for fewer jobs, the Times reported.The figures come as the administration grapples with the overwhelming influx of illegal immigrants across the southern border, many of them children hoping to benefit from President Barack Obama's nondeportation policies.GOP lawmakers also blame the president for lax border security and have signaled that the chances for the House taking up immigration reform legislation during this Congress are dead.