With 2006 fast coming to a close, the District on Friday reported what is surely cause for celebration — the city’s homocide tally, once one of the highest in the nation, is down, and dramatically so. According to current statistics, the District has suffered 156 homicides this year, 18.3 percent less than the same time in 2005 and 35 short of last year’s total of 191. Short of a citywide killing spree in the next 14 days, this year’s mark will follow a downward trend since the shameful days of the early- to mid-1990s, when homicides hovered around 400.

The news is sure to be gold to Williams, who is looking to cement something resembling a positive legacy in his final days in office. On the other hand, it adds certain weight to incoming Police Chief Cathy Lanier and mayor-elect Adrian Fenty, both of whom are looking to improve upon the work of Williams and current chief Charles Ramsey.

The stats beg the difficult question — how? What has pushed the District’s rate of homicide down so dramatically this year? Was it the crime emergency imposed soon after the killing spree this past summer? Was it simply the product of shifting demographics, with crime following the displacement of many of the city’s poor into neighboring Prince George’s County? Is it a product of new law-enforcement technologies or firearm recoveries, which have surged over the past four years? Did Williams and Ramsey stumble across a succesful and sustainable strategy to combat violent crime?

We’re on the fence. While we long criticized the imposition of a crime emergency, A seems to have followed B — more cops were forced to work longer hours for months on end, and homicides and other violent crime declined. But is it causation or correlation? Was the spike in violent crimes during the summer merely seasonal, and would homicides have fallen off with or without the emergency? We’re still trying to figure it out.

Regardless, any drop in crime is a welcome one, especially when the FBI is expressing concern over nationwide increases in violent crime. Should the city hold for the next two weeks, a 35-body drop in homicides will be historic.