Gun deaths worldwide total about 250,000 yearly and the United States is among just six countries that make up half of those fatalities, a study found.

The results from one of the most comprehensive analyses of firearm deaths reveal "a major public health problem for humanity," according to an editorial published with the study Tuesday in the Journal of the American Medical Association.

Although recent headlines make it seem like gun killings are surging globally, the new figures tell a more nuanced story.

Researchers counted about 209,000 gun deaths in 1990 compared to 251,000 in 2016. The average rate, about 4 per 100,000 people, was mostly unchanged.

Two-thirds of the deaths in 2016 were homicides, although the U.S. is among wealthy countries where suicides by gun outnumber gun killings, the study found.

The numbers reflect more than "how many guns are around in a country," said lead author Dr. Christopher Murray, a professor of health metrics at the University of Washington. Cultural beliefs about guns and suicide vary widely around the world, he noted, adding, "That's where we get this incredible range of firearm deaths."

There were larger increases in many of the 195 countries involved in the study, particularly in Central American and South America, where the rates reached nearly 40 per 100,000 in some places. Researchers said the drug trade and economic instability may have contributed.

Brazil, Colombia, Guatemala, Mexico and Venezuela are the countries that with the U.S. contributed to half the study deaths. The study raises concerns about the lack of research on causes of gun violence and ways to prevent it, the editorial said.

Among the findings:

—In 2016, 64 percent of global gun deaths were homicides, 27 percent were suicides and 9 percent were accidental.

—Gun deaths in the U.S. climbed from 35,800 in 1990 to 37,200 in 2016, but the rate dipped slightly to 11 per 100,000. Gun suicides increased from 19,700 to 23,800.

—The U.S. had the second-highest gun suicide rate in 2016, just over 6 deaths per 100,000 — a slight dip from the 1990 rate. Greenland had the highest, 22 per 100,000 but that amounted to just 11 suicides.

—El Salvador had the highest global gun death rate, nearly 40 per 100,000 people. Singapore had the lowest, with 0.1 death per 100,000.

—Gun deaths outnumbered deaths from combat and terrorism every year except 1994, when 800,000 people died in Rwandan genocide.