—AMIS insured cars
The Encuesta Nacional de Victimización y Percepción sobre Seguridad Pública (ENVIPE) is national victimization survey that allows us to compare crimes reported to the justice system with all crimes committed in the country. Blue lines are crimes reported to the justice system and magenta the estimates of total crimes in Mexico via survey. The 'unrecorded' crime rate (the percentage ornumber of offences which is not notified the police) was 93.6% at the national level in 2016 and 93.7% in 2015. We can also compare car robberies with the number of insured vehicles that were reported stolen by the AMIS (Mexican Association of Insurance Institutions)
There are two official sources of homicide information in Mexico: the vital statics published by the INEGI, based on death certificates; and those from the SESNSP (justice system), based on police investigations. The statiscs from the SESNSP are available in two ways: as the number of police investigations and as the number of victims contained in those investigations. Additionally, in January 2018, a new methodology for classifying crimes was made public, and feminicides (the intentional killing of females because they are females) were no longer included in homicide counts and moved to their own crime category. Because of all this there are many ways of reporting the number of homicides in Mexico. If you don't mind waiting a year of so, you can just use the INEGI data, but for the most recent data the most accurate method is to sum the number of victims of homicide and the number of victims of feminicide using the new methodology.