But hate crimes remain vastly underreported. Only 12.6 percent of the agencies in the F.B.I. report indicated that hate crimes had occurred in their jurisdictions in 2017. Agencies as large as the Miami and Las Vegas Metropolitan Police Departments reported zero. (A spokeswoman for the Las Vegas police later said that the report was made in error and that there were actually 61 in the jurisdiction last year.)

“I wouldn’t feel too confident in those numbers,” said Sim J. Singh, the senior advocacy manager for the Sikh Coalition, a civil rights organization. Data shows that hate crime victims often do not trust that reporting will help them.

There are agencies taking steps to enhance law enforcement reporting. Will Johnson, the chief of police in Arlington, Tex., and a vice president of the International Association of Chiefs of Police, said that some departments lack the proper training for identifying and reporting hate crimes. Last year, the chiefs’ association passed a resolution encouraging law enforcement agencies to collect, analyze and report on hate crimes.

“More importantly than anything else is the effective conversation and heightened awareness in communities that this is important and that government institutions are prepared to respond effectively to crimes that victimize broadly across our communities,” Chief Johnson said.

The F.B.I. said it planned to train law enforcement officers next year on how to do a better job of identifying and reporting bias-motivated incidents. The Justice Department has also launched a new website on hate crimes.