Legislators have been told it’s difficult to calculate the economic impact of Mississippi’s illegal immigrant population because few entities track the data.

Sam Atkinson, who works at the state Auditor’s Office, told the Senate Judiciary A Committee on Wednesday that some estimates are based federal reports, including those from the U.S. Department of Homeland Security.

Atkinson says the auditor’s office is awaiting the latest Census statistics to update a 2006 report that said illegal immigrants cost the state $25 million in medical, educational and correctional services.

The committee held hearings this week to examine a proposal similar the law passed in Arizona that lets law enforcement check the status of individuals suspected of being illegal immigrants.