WASHINGTON — Immigrants facing deportation are increasingly finding success in immigration courts, according to a new analysis of court data.

Nearly half of immigrants facing deportation have won their cases in the last year, according to the Transactional Records Clearinghouse at Syracuse University, which collects and studies federal prosecution records.

The government has been losing more deportation cases each year since 2009.

The analysis published Thursday does not say how many deportation cases Immigration and Customs Enforcement, whose lawyers represent the government in immigration courts, successfully appealed to the Board of Immigration Appeals. The government can appeal immigration court rulings to the Board of Immigration Appeals, part of the Justice Department.

Since the start of the 2014 budget year in October, immigration judges ruled in favor of immigrants in about half of the 42,816 cases heard, TRAC reported. In 2013 the government won about 52 percent of the cases.

Immigrants in California, New York and Oregon have been most successful recently, while judges in Georgia, Louisiana and Utah have sided more often with the government, according to TRAC.

“ICE’s enforcement strategies and policies are designed to prioritize its resources on public safety, national security and border security threats,” said ICE spokeswoman Gillian Christensen. “ICE continues to focus on sensible, effective immigration enforcement that prioritizes the removal of criminal aliens and those apprehended at the border while attempting to unlawfully enter the United States.”

Immigration supporters accuse the Obama administration of deporting too many people, but Republicans say the president is too lenient on immigrants living in the country illegally. Nearly 2 million immigrants have been removed by Immigration and Customs Enforcement under President Barack Obama.

It’s unclear what has prompted judges to side with a growing number of immigrants fighting to stay in the country. Immigration laws have not changed in recent years, but the Obama administration has changed how it enforces immigration laws.

In 2011, the government reviewed hundreds of thousands of cases pending in immigration courts. The effort was designed to curtail the backlog of more than 300,000 pending cases. Tens of thousands of cases were eventually dismissed, but there are now more than 360,000 cases pending, according to TRAC.

And the Obama administration has since issued policy orders directing immigration authorities to exercise discretion when deciding which immigrants living in the country illegally should be deported. Then-Homeland Security Secretary Janet Napolitano said discretion should be used for immigrants who didn’t pose a threat to national security or public safety.

In 2012 Obama also created a program called Deferred Action for Childhood Arrivals to allow tens of thousands of young immigrants living in the United States illegally to apply to stay in the country for up to two years and get a work permit.

Kathleen Campbell Walker, an El Paso, Texas, immigration lawyer, said it may be too soon to know what the TRAC data means for immigration enforcement. She said immigration court backlogs mean cases now being heard by immigration judges could be years old. And though immigration laws have not changed in recent years, some immigrants may be more successful in arguing that they should be allowed to stay in the country based on those discretion memos.

“The true implications of these numbers are murky and people shouldn’t jump to conclusions yet,” Walker said.

Obama pledged during both of his presidential campaigns to overhaul the country’s immigration laws.

The Democratic-led Senate passed a wide-ranging bill last year but similar legislation has stalled in the Republican-controlled House.

Last month, House Republicans announced immigration principles that touched on both border security and the fate of the more than 11 million immigrants thought to be living in the United States illegally. A week later, however, House Speaker John Boehner said it would be difficult for an immigration bill to pass this year.

“The American people, including many of our members, don’t trust that the reform we’re talking about will be implemented as it was intended to be,” Boehner told reporters at his weekly news conference earlier this month.

The administration has made several immigration policy changes in recent years and during his State of the Union address last month, Obama pledged to keep using his authority to address a variety of issues that Congress hasn’t addressed.