A new audit has revealed that the U.S. Border Patrol is finding it difficult to find and keep agents. The results released Wednesday indicate that while the agency hires approximately 523 people a year, they lose 900 on average to other agencies or due to varying professional requirements.

The difference in hiring versus loss has left the agency short of nearly 2,000 agents, according to a broad survey by the Government Accountability Office (GAO) that analyzed staffing and deployment challenges at the agency.

As of May, the Border Patrol had 19,500 agents, but the law states that the agency must have a minimum 21,370 agents employed. Stack that against President Donald J. Trump’s demand to hire a workforce of 26,370, an increase of 5,000 over the previous minimum, and the deficit grows to 6,870.

The GAO looked at several factors, including how the agents are used. According to agency managers, working conditions, competition with U.S. Immigration and Customs Enforcement, and certain policies are contributing to the deficit.

One of the policies in question is the use of agents at highway checkpoints. While some within the agency feel the checkpoints are a vital tool in finding drugs and illegal immigrants, others think they are ineffective because they are easy to avoid. Range of deployment is also an issue with the checkpoints, as the Border Patrol only has authority up to 100 miles from the border. That brings into question other issues, such as the constitutional rights of those they stop at the checkpoints.

Although the shortage affects the entire agency along the southwest border, the staffing problem is greatest in eastern California and western Texas.