For New Yorkers of a certain age, photos of empty New York City streets evoke a particular question: How much safer is the city when everyone is being asked to stay at home? It’s by no means the most important question at the moment, as thousands continue to die each week of covid-19, the disease caused by the coronavirus that has spread across the world. But it’s a question that to some degree captures a sense of the extent to which life in New York has changed.

The answer, in short, is that crime has fallen. Data reported by the New York Police Department through its CompStat system show that the number of major crimes committed in the city over the past 28 days are down by about 30 percent relative to the same period in 2019. That includes a few days before the lockdown, which was announced on March 20. In recent days, the drop relative to a year ago has been about a third.

That drop isn’t consistent across categories. There were 20 homicides in the city during the period from March 16 to April 12 last year. This year, the count is only down to 18.

A more sweeping contrast: Reported grand larcenies are down substantially. Burglaries, though? About where they were last year.

There’s some variance here that’s a function of days of the week. If we take a three-day average of the reported crimes, the year-over-year change in recent days has been closer to a 40 percent drop. You can see how that drop expanded after the stay-at-home order was announced.

Again, though, you see variance by type of crime. Car thefts are up a bit, along with burglaries. Robberies and assaults are down.

There’s also a divergence by geographic area. In the precincts that make up the “patrol borough” of Queens North, the three-day average of overall major crimes was actually up over 2019 for much of last week. The drop has been steeper in Manhattan than elsewhere, particularly in the Manhattan South patrol borough.

This finding brought to mind a terrific map from the local news site the City. Using data from the Department of Sanitation, it shows the relative change in how much trash has been picked up across the city. Areas in green have seen more trash pickup; purple, less.

The implication? That areas with more purple have seen more people leave the city in light of the pandemic. The island of purple near the center is Manhattan. The dark green at center right is northern Queens.

What may be the most important takeaway of this analysis is what it shows didn’t happen. Asking New Yorkers to stay home pushed down the crime rate — somewhat. There’s still a decent amount of crime in New York City, even in the midst of a massive health crisis.

For many New Yorkers, this will probably be a point of quiet pride.