According to the survey -- which sampled 726 men and 95 women and was done by the Centro de Investigacion y Docencia Economicas (CIDE) at the behest of the government (see pdf of report below) -- over 60 percent of these prisoners are in jail for drug trafficking crimes: transportation, local sale, sale in bulk, trafficking, pushing, possession, and consumption. An astounding 80 percent of the women jailed are in for drug crimes. The rest are in jail for a mix of weapons charges, organized crime, homicide and kidnapping.

Half were caught "in the act." Of those who were not, 92 percent said they saw no arrest warrant. Close to 60 percent said they were beaten while in detention. More than half said they were taken somewhere other than the police station before they were officially arrested, including military garrisons, state agencies and "clandestine houses."

Forty-four percent said they did not have a lawyer present when they were questioned by state investigators. The same percentage said the lawyer they had during their trials did not explain what was happening; 51 percent said their lawyers did not give them any advice and 39 percent said their lawyers did not explain the results of these trials to them.

Men far outnumber women in the prisons, but nearly all come from disadvantaged backgrounds. Ninety percent of men and 87 percent of women began working before their 18th birthday, and one-third began working before their 12th birthday. Most of the men and nearly half the women left school in order to work.

More than half stopped living with their fathers before their 18th birthday. A third have relatives in jail. Forty percent of men and 60 percent of women had their first child between ages of 18 and 22. A third left their homes because of violence, and nearly half reported that someone in their home consumed alcohol at very high levels.

InSight Crime Analysis

Mexico is living through a prison boom not unlike that seen in the United States. Since the mid-1990s, the proportion of the population in prison has nearly doubled, going from 103 inmates per 100,000 inhabitants in 1996, to 204 per 100,000 in 2012.

The reasons for this rise are many: the general public now reports more crimes; changes in the law set higher penalties for those crimes; and penal authorities have an increasing tendency to prolong prisoners' stays in jail for bad behavior.

As of January 2012, there were 233,000 prisoners in Mexico, 48,000 of whom were prosecuted for federal crimes. Criminals are spread amongst 12 federal prisons and the 406 state, municipal and capital city prisons.

The results of the survey fit with a trend that has been emerging since the 1990s: Mexico has become an increasingly important transit nation for drug trafficking, and a point of distribution. This shift has led to higher levels of incarceration and to increased levels of violence in the country.

Close to half of those prosecuted had been transporting illegal drugs in one form or another. The survey teased out a little more detail by asking the participants the type and the value of the drugs they were caught with: close to 60 percent were captured with marijuana, and just over 27 percent with cocaine; 27 percent said the value of the drugs was above $100,000.

The kidnapping results were also interesting, as close to two-thirds of those surveyed who had committed the crime said they knew their victim, who they described as "relatives," "co-workers," "neighbors," "someone I knew," or "boss." Most of these kidnappers worked in small groups of three or less. This contradicts the public perception of kidnapping as a crime dominated by large criminal groups, and speaks of a much more localized practice, carried out by specialized groups.

Finally, it is worth re-emphasizing the institutional violence in Mexico's prisons, and the systematic way in which the accused are refused their rights to due, competent counsel. This survey is focused on the prisoners, but it paints a picture of an entire judicial system in crisis.