Fairfax County police working a checkpoint, seeking witnesses while trying to solve a homicide. Only 11 homicides were committed in the county of 1.1 million last year, a very low number. (Rich Lipski/The Washington Post)

For the Big Seven — murder, rape, robbery, aggravated assault, burglary, larceny and autho theft — the grand totalreported in Fairfax was 16,209. In 42 years, that number has never been below 17,000. The previous low was 17,108 in 2006. In addition, the total number of burglaries reported in 2011 was by far an all-time low: 1,021, in a county of 1.1 million. In the 1970s, the total was 5,000 per year, but Fairfax has steadily decreased it to this in­cred­ibly low figure, even as the population has steadily increased, making Fairfax’s crime per capita statistics even better..

It was the third straight year of declines for Fairfax, this time a 7.1 percent drop. Robberies increased slightly, but larcenies, which at 13,000+ make up the largest proportion of the Big Seven (called Part I crimes by the FBI), dropped by 6.5 percent. Auto theft also hit an all-time low, 881. I am hoping for more insights on all this from Fairfax police commanders later this week.

Meanwhile, two last things to chew on, statistically speaking: One, Fairfax switched from Uniform Crime Reporting to the National Incident-Based Reporting System several years ago. But that requires an agency to report all crimes in an incident, not just the most serious one under the UCR system, so the numbers theoretically should have gone up, not down. And two, Fairfax in 2010 switched to new I/LEADS software for all of its crime reports, ticket writing, statistical tracking, everything. But could that make thousands of crimes disappear? Let’s hope not. Here are the numbers:

2010 2011
Murder 16 11
Rape 74 72
Robbery 394 423
Agg.Assault 450 392
Burglary 1211 1021
Larceny 14345 13409
Auto Theft 963 881
Totals 17453 16209