U.S. Interior Illegal Immigrant Deportations Declined 34 Percent; 167,000 Convicted Alien Criminals Remain At Large By Staff Reporter | Oct 16, 2014 03:40 PM EDT A new report released Wednesday by the Center for Immigration Studies shows that deportations from the interior of the U.S. declined 34 percent in the past year, largely due to what is described as "consistently lower levels of enforcement activity, particularly in the interior." That's 58 percent lower than at their peak in 2009. Of the 585,000 aliens encountered by ICE agents in 2014, only 143,000 underwent deportation processing, with the other 442,000 being released. And out of the 897,572 aliens who have remained in the U.S. after receiving a final order of removal, a whopping 167,000 are convicted criminals who "were released by Immigrations and Customs Enforcement (ICE) and are currently at large," said the report. "Prosecutorial discretion as practiced by the Obama administration has transformed immigration enforcement into a massive catch-and-release program that makes a joke of the law, fails to deter illegal settlement, and allows even illegal aliens who commit crimes to remain here," said Jessica Vaughan, director of policy studies and author of the report. "These policies inflict real harm on Americans and legal immigrants in the form of lost jobs, depressed wages, additional social services, and even lost lives. In addition, with the rise of ISIS and other terrorist groups around the world, our lax policies represent an unnecessary national security risk." Watch video Vaughan based her report on data released on Sept. 22 by the Statistical Tracking Unit of the Office of Enforcement and Removal Operations of U.S. Immigration and Customers Enforcement. In just one year, the number of "non-departed" aliens grew by more than 25,000, said Vaughan, noting, "As of the end of the 2013 fiscal year, the total number of post-final-order aliens remaining in the country was 872,504." The statistics show that interior enforcement activity is in a "state of collapse," allowing tens of thousands of criminal aliens back into American communities and serving as an invitation to foreigners who "wish to inflict harm on Americans to take advantage of our lax policies," said Vaughan. "Congress can affect this situation by restraining further executive action that would shield even more illegal residents from enforcement, and by insisting that the executive branch agencies spend the public funds they receive to carry out their enforcement mission in a way that is consistent with congressional and public expectations," she concluded.