Two counties in Northern Virginia are among the 62 jurisdictions that prosecuted the majority of criminals executed in the United States in recent decades, according to a new study.

An analysis released Wednesday by the D.C.-based Death Penalty Information Center found that while 32 states allow for capital punishment, most jurisdictions don’t use it. Two percent of the counties in the country were responsible for 685 of 1,320 executions from 1976, when the Supreme Court reinstated the death penalty, to 2012.

Harris County, Tex., executed 115 inmates, by far the largest total of any county. Jurisdictions in Texas, Oklahoma, Missouri and Arizona had executions numbering in the double digits.

In Northern Virginia, Prince William County had nine death row inmates who were executed, and Fairfax County had five.

Among the most high-profile executions arising from a Prince William case was that of John Allen Muhammad, who was part of a sniper team that gunned down 10 people in the Washington area in 2002. Federal authorities chose to prosecute Muhammad in Prince William in part because of Commonwealth’s Attorney Paul B. Ebert’s record in capital cases. He has sent more than a dozen people to Virginia’s death row.

Richard Dieter, the executive director of the Death Penalty Information Center, said the study shows that criminals face vastly different odds depending on where their crimes were committed.

“There’s an arbitrariness to the death penalty,” he said. “Most of the counties in Virginia have never had an execution in this modern era.”

Maryland repealed the death penalty this year, and the District also does not have capital punishment.

Ebert said he seeks death sentences for criminals who are “the worst of the worst.”

“Very few qualify for” capital punishment, Ebert said. “For some reason, Prince William seems to get people who qualify.” Some prosecutors in the state favor the death penalty but have stopped enforcing it because of the expense and difficulty, he said. “We’re sworn to enforce the law that exists, and it’s repugnant to me to think that you’re going to administer justice based on finances.”

In the most recent execution in a Prince William case, Paul Warner Powell, who murdered one woman and raped and nearly killed her sister, died in Virginia’s electric chair in March 2010. A 60-year-old man who was executed a year earlier had killed a young couple.

Another recent Prince William death sentence was overturned by a federal court because of the mishandling of retracted testimony. But the U.S. Court of Appeals for the 4th Circuit ruled in May that the District Court judge went too far in halting a retrial, and prosecutors are free to pursue a new case against Justin Michael Wolfe in a drug-related killing.

Prince William is tied for 20th on the list of counties which have had inmates executed since 1976. There are seven counties smaller than Prince William, with its population of about 430,000, that saw as many or more executions in the past three dozen years.

Fairfax County is No. 42, with five executions and a population of more than 1 million.

According to the Death Penalty Information Center, Mir Aimal Kasi, who died by lethal injection in 2002, was the last Fairfax County inmate executed. He opened fire outside CIA headquarters in 1993, killing two people and wounding three others.

In recent years, the use of capital punishment across Virginia has declined dramatically. The state has had fewer death sentences in the past five years than any period since the 1970s. While polls find a majority of Americans still favor capital punishment, support has been steadily declining since the mid-1990s.

Virginia’s Chesterfield (8), Virginia Beach City (8), Hampton City (5), Pittsylvania (5) and Portsmouth City (5) were also listed in the study.