The Whitman-Walker Clinic, a longtime service provider for the AIDS and HIV community, is seen on 14th Street on June 4 in Washington. (Charles Ommanney/The Washington Post)

The number of newly diagnosed cases of HIV and the deaths related to the illness continued to drop in the District in 2013, although overall prevalence of the virus remained at epidemic levels, according to data released Tuesday by the city.

As of December 2013, 16,423 D.C. residents — 2.5 percent of the city’s population — were living with HIV, up from 16,044 the year before.

Washington, however, appeared to improve in nearly every other area.

Deaths decreased by 44 percent, the most significant decline in years. The number of new diagnoses decreased from 678 to 553, with declines among blacks, whites and Hispanics. Although three children were born with the virus in 2012, not one was perinatally infected in 2013.

“My administration is committed to drastically reducing the incidence of HIV in the District of Columbia,” Mayor Muriel E. Bowser (D) said in a statement. “And we are equally committed to making sure those who are diagnosed with HIV receive the best care in the nation.”

The mayor, who presented the latest findings at a Whitman-Walker Health clinic in Southeast, also announced a series of goals to achieve by 2020: for 90 percent of residents with HIV to know their status; for 90 percent of those infected to be in treatment; for 90 percent of those infected to achieve viral load suppression; and for the District to see a 50 percent decrease in new cases.

The city has made steady progress since 2009, when a D.C. official stunned the public by declaring that rates in the capital were “higher than West Africa.”

The number of new diagnoses fell 40 percent (by 363) between that year and 2013.

“The precipitous drop in new HIV cases in recent years has been nothing short of remarkable,” Whitman-Walker Health Executive Director Don Blanchon said in a statement. “We’ve also made tremendous progress in keeping people who test positive engaged in care.”

The city said that 80 percent are linked to care within three months of their diagnosis and 62 percent are retained in care.

The data found a drop in newly diagnosed HIV cases linked to drug use by injection. In 2007, before the city’s needle exchange program was scaled up, 149 people were infected that way. In 2013, 19 were.

Sex between men remains the top cause of transmission, making up 46 percent of new cases.

African Americans accounted for 75 percent of the 2013 diagnoses, a proportion that is consistent with past years. About one in 17 black men in the District was infected with the virus.

Six percent of residents ages 40 to 49 and 6.7 percent ages 50 to 59 were infected.

Still, the number of residents diagnosed with AIDS fell by the largest percentage since at least 2009, dropping from 393 in 2012 to 296 in 2013.

“Now,” Blanchon said, “the question is how we get to zero, and what we need to do to reach the most marginalized communities that face the brunt of the HIV epidemic, namely young people, gay and bisexual men of color, and transgender people.”

Dana Hedgpeth contributed to this report.