NASHVILLE, Tenn. -- New numbers from the Davidson County Jail show a drop in the percentage of illegal immigrants arrested.

Related: Watch This Story | Special Section: Immigration In U.S.

The numbers are down from 8.8 percent of the newly arrested illegal immigrants in April 2007 to 5.2 percent in October 2007.

"One of the big things we hope is that people are making better decisions about committing whatever kind of crime it might be," said Karla Weikel of the Davidson County Sheriff's Department.

The sheriff's department doesn't know exactly what is causing the decrease, but local immigration experts, like attorney Sean Lewis, have their theories.

"I feel, because I can only guess, that it's the economy," said Lewis.

There are fewer immigrants in Nashville because they're leaving since they can't find work, said Lewis.

"I had a case today where they came in, and they normally do 15 houses a year at a construction company, and he came in today and said, 'In the past year, we did three houses,'" said Lewis.

Since April 2007, when the Davidson County Sheriff's Department started a partnership with federal authorities, they've begun removal proceedings against 4,500 people.

"These people are being removed from our community, and even if they do come back to the United States, we hope that they won't come back here," said Weikel.

The decrease in illegal immigrant crime could also be due to a public relations campaign focused toward Spanish-speaking immigrants. It warns them if they drive without a license, they could go to jail and get deported.

The Sheriff's Department said since April 2007, it has found 211 cases in which illegal workers who were arrested in Nashville had already been ordered to be deported. However, they simply never left.