The border region in the American Southwest is not seeing nearly as many illegal immigrants. But it is still experiencing a high number of deaths among those making the dangerous trek to reach the U.S.

Over a four-year period, the number of people caught trying to cross the border dropped by 62%, from 858,638 in 2007 to 327,577 in 2011.

During this same span, Customs and Border Protection officers reported a dip in fatalities along the border, from 398 to 368. But due to the larger decline in crossings, the ratio of deaths to arrests more than doubled, from .05% to .11%. It is looking like 2012 may turn out to be a worse year. In the Rio Grande Valley in Texas alone, 150 have been found dead, double the number from the previous year. According to NBC News, in small Brooks County in South Texas, the remains of 50 immigrants were found in 2011. This year the number has already reached 104. Most of the victims came from Central America.

The main reasons for the increased death toll this year are thought to be extreme heat and drought conditions, as well more aggressive border enforcement that has forced human smugglers to venture into more hostile terrain.

-David Wallechinsky, Noel Brinkerhoff

To Learn More:

Deadly Crossing: Death Toll Rises Among Those Desperate for the American Dream (by Hannah Rappleye and Lisa Riordan Seville, NBC News)

Border Crossing Deaths More Common As Illegal Immigration Declines (by Carolina Moreno, Huffington Post)

Fish and Wildlife Service Allows Water Stations for Illegal Immigrants on Public Land (by Noel Brinkerhoff, AllGov)

Arizona Man Convicted of Leaving Drinking Water in Desert (by Noel Brinkerhoff, AllGov)