James B. Comey, the director of the F.B.I., told lawmakers last year that it was “embarrassing” that the news media could produce better data than his own agency on such an important issue.

“We can’t have an informed discussion because we don’t have data,” Mr. Comey told the House Judiciary Committee last October.

“People have data about who went to a movie last weekend, or how many books were sold, or how many cases of the flu walked into the emergency room,” he said, “and I cannot tell you how many people were shot by police in the United States last month, last year, or anything about the demographic. And that’s a very bad place to be.”

According to the Post database, 991 people were fatally shot by the police last year, and 754 have been so far this year.

Under the Justice Department plan, the F.B.I. is to begin a pilot program early next year to assemble data on the use of force by about 178,000 agents at major federal law enforcement agencies including the Drug Enforcement Administration, the Marshals Service, the Bureau of Alcohol, Tobacco, Firearms and Explosives, and the F.B.I. itself.

In addition, the Justice Department plans to begin collecting data from local and state law enforcement departments on “in custody” deaths — not just in shootings, but in cases of suicide and natural death as well.