The federal government deported 25 percent fewer illegal immigrants in the first half of fiscal year 2015 than in the same period the previous year, according to figures provided to Congress, reported the Washington Times.

Since the beginning of the fiscal year on October 1, the government only deported 117,181 illegal immigrants, compared to 157,365 during the same period last year.

In the last three years, deportations dropped 41 percent, almost perfectly coinciding with the beginning of President Obama's 2012 Deferred Action For Childhood Arrivals (DACA) amnesty program, indicating that Obama's immigration amnesty program is actually hampering removal efforts.

"This is a stunning free fall in enforcement activity, not just deportations but arrests too," Jessica Vaughan, policy studies director at the Center for Immigration Studies, told the Times. "It turns out that even criminal arrests and deportations have dropped, including those of the 'worst of the worst' Level 1 felons, and the huge numbers of criminal releases continues."

DACA granted temporary legal status and work permits to younger illegal immigrants, and last year, additional amnesty, legal status and working permits were provided to millions more illegal immigrants.

Obama said the policy would encourage law enforcement agents to pursue dangerous criminal aliens while providing "deferred action" to law abiding immigrants, but as of April 4, 2015, the government had removed 30 percent fewer criminal immigrants compared to the same period last year, according to the Times.

ICE and Homeland Security officials said they are budgeted to deport some 400,000 immigrant per year, but at the current pace they will deport less than 250,000 in 2015, the Times reported.

The Times notes that the decrease in deportations could undercut the Obama administration's ability to justify its amnesty program.

Spokeswoman for U.S. Immigration and Customs Enforcement (ICE), Gillian Christensen, told the Times that deportations have dropped due to changing demographics of illegal immigrants. More immigrants are coming from Central America, which are more costly to detain and deport.

"Removals of non-Mexican nationals require additional detention capacity, efforts to secure travel documents from the host country and the arrangement of air transportation," she said. "As a result, more time, officer resources and funding are required to complete the removal process for nationals from Central America and other noncontiguous countries as compared to Mexican nationals apprehended at the border."

ICE's deportation efforts have also been slowed by more than 200 states, cities and counties that have enacted laws and ordinances preventing police from working with federal immigration authorities on the grounds of unconstitutionality. States and local authorities often refuse to hold immigrants until ICE is able to pick them up.

"When laws and ordinances are passed limiting the use of detainers, ICE must expend additional staff and resources to develop and execute operations to locate and arrest convicted criminals at large," Christensen said.

ICE stopped asking local authorities to hold immigrants following Obama's newest amnesty in November, and are now developing a program that would ask jails and prisons to notify ICE before releasing an illegal immigrant.