Tucson’s homicide rate declined slightly in 2013, although it remains above the national average, new data show.

To date in 2013, the city has had 44 homicides, Tucson police say. When calculated against the estimated population of nearly 525,000 people, the homicide rate stands at 8 per 100,000 residents.

Nationwide, the homicide rate was 4.7 per 100,000 people, according to a report released this week by the U.S. Justice Department Bureau of Justice Statistics.

In 2011, the last year the report was analyzed, there were 14,610 homicides in the U.S.

Despite a rate higher than the national average, the homicide rate in Tucson appears to be trending down, matching the national trend.

At 8 homicides per 100,000, the figure stands slightly below 2012, with 9 per 100,000 and 2011, at 10 per 100,000. The average rate since 1990 has been 10 per 100,000 people.

In the unincorporated portions of the county, the jurisdiction of the Pima County Sheriff’s Department, there were 16 homicides to date in 2013. That puts the rate at about 4 per 100,000, well below the average rate of 7 since 1990.

The regional trend also has sloped downward.

The combined homicide rate in Pima County, when taking totals from the Tucson Police Department and Pima County Sheriff’s Department, was 6. The average regional homicide rate since 1990 has been 10 per 100,000 residents.

The homicide figures do not include smaller police jurisdictions in Pima County, like South Tucson, Sahuarita, Marana and Oro Valley.

The Justice Department report, titled “Homicide in the U.S. Known to Law Enforcement, 2011,” said the national average of 4.7 homicides per 100,000 people represents the lowest level since 1963.

The rate and overall number of homicides in the United States as a whole have fallen consistently since 1992, when nearly 25,000 homicides were committed and the rate stood at 10 per 100,000 people.

It’s difficult to pinpoint why the country has seen such dramatic drops in crimes such as homicide, said John Firman, director of research with the International Association of Chiefs of Police.

“Homicide is one of the most complex crimes to investigate,” Firman said.

He said a combination of factors could have an impact on lowering crime rates. For example, policing methods have grown in sophistication, with many departments taking a more systematic approach to crime prevention.

“The community outreach has to be massive and in advance,” Firman said.

He said the Washington, D.C., Police Department has used social media to spread the word about a program that lets residents anonymously text crime tips to police.

Other factors include using verified best practices and having the right staffing levels to do the job.

Even some large cities once known for high crime rates have experienced steep declines in violent crimes in recent years.

New York City once was a haven for violent crime, with more than 2,200 homicides in 1991.

By 2012, the number of homicides fell to 414 with the homicide rate dropping to 5.1 per 100,000, a rate lower than Tucson’s, according to FBI crime statistics.

Contact reporter Patrick McNamara at 573-4241 or mcnamara@azstarnet.com. On Twitter @pm929.