The Charlotte-based endowment created in 1924 by industrialist James B. Duke has officially passed the $3 billion mark for grants distributed in the two Carolinas.

Duke Endowment officials said it took just eight years for the nonprofit to give away the last billion dollars, which included a well-publicized $45 million grant for Davidson College.

It took 68 years to distribute the first $1 billion and 12 years to give away the second billion.

James B. Duke is the founder of Duke Energy, but the endowment and the energy company are not connected. Duke University is also named for the family but not connected to the endowment.

The New York City-based Foundation Center ranks the Duke Endowment among the 50 most generous in the country, a list that puts it in the company of such nonprofits as the Bill & Melinda Gates Foundation and Rockefeller Foundation.

Two other North Carolina foundations are on that list: the Bank of America Charitable Foundation and the GlaxoSmithKline foundation.

The Duke Endowment, which has nearly $2.9 billion in assets, is the largest private endowment in the Southeast. It was created with $40 million from James B. Duke, who specified that grants be focused in the Carolinas on four areas: child care, health care, higher education and rural churches.

The most recent billion dollars included help for initiatives that brought uniformity to the work done by child advocacy centers.

It also included a new effort that tackles health problems among North Carolina’s United Methodist clergy in rural areas. Endowment President Eugene Cochrane says that effort emerged as a $12 million investment after endowment staff noticed an increasing number of Methodist clergy it met with were obese or in poor health.

“We realized that heart disease, diabetes and mental illness rates of clergy members were worse than that of the average North Carolina citizen,” Cochrane said.

“In rural communities, they are without a lot of resources and professional networks,” Cochrane added. “So I think there’s a factor of loneliness. … It goes to the core of that question: Who takes care of the minister?”

The program pairs United Methodist clergy members with a wellness advocate who serves as a coach. Other aspects include access to online stress reduction and weight-loss programs.

Robin Swift, director of the Clergy Health Initiative at Duke Divinity School, said the endowment program is also strengthening rural churches, which are often unable to afford the health insurance required to have a full-time pastor.

“I believe the effort is saving lives,” Swift said. “We’ve heard from people who were psychologically at the end of their ropes.”