Mexican prosecutors say one in three drug trafficking suspects received prison sentences during the first five years of President Felipe Calderon's administration.

The report from the federal Attorney General's Office says Mexican drug enforcement authorities recorded 3,439 drug suspects arrested, but only 1,072 actually went to prison. The report doesn't specify what happened to the other suspects arrested.

The report says authorities made the most drug trafficking arrests in 2009, with 866 suspects detained and 122 sentenced to prison. Last year, authorities arrested 772 suspects and sent 574 to prison. The report says the Mexican justice system was being reformed during the period studied.

Mexican officials also extradited 502 people between Dec. 1, 2006, and the end of 2011, with 478 of them sent to the United States.