“Our frustration is that they have some information and some numbers, something that would be valuable and they are not releasing them,” said Eric Olson, a security expert at the Woodrow Wilson International Center for Scholars in Washington. “And there is a whole bunch of other things that are not well defined and can lead to erroneous conclusions.”

The number of drug-related deaths is the subject of much dispute. Government officials last gave a figure — 34,612 — at the end of 2010, promising to update their tally regularly. They did not follow through. A group of Mexican and American academics, including Mr. Olson, began pleading with the Calderón administration for death figures, along with other data known to be collected, including violent episodes involving the military. But members of the group say they were ignored.

Pressure began to mount late last year as the government received several public records requests seeking information on crime-related deaths nationwide. The Calderón administration initially said that the data was confidential for reasons of national security, then last week the government said that the figures would be published after further study. The release on Wednesday came after Mexico’s freedom of information agency said it would ask for an investigation if the data was not released.

Now, the question is whether the report accurately reflects the reality on the ground. Some Mexican news organizations have arrived independently at similar totals, whereas others have found that the government regularly undercounts the number of drug-related deaths.

“Since there are very few actual investigations, those are approximations at best,” Mr. Olson said. “They’re hunches. There is not really a way of knowing precisely if it was caused by organized crime or a drug trafficker or not.” Molly Molloy, a librarian at New Mexico State University who closely tracks deaths in Ciudad Juárez and other parts of the country, said that given the investigative failures, the most reliable figures come from the Mexican census agency, which identified 67,050 homicides from 2007 through 2010, nearly double the government’s count of drug-related deaths for that period.