The suicide rate among middle-aged Americans rose by 28 percent between 1999 and 2010, the Centers for Disease Control and Prevention said in a report released today, the largest increase among any age group. The disturbing finding, researches say, suggests some of the focus on suicide prevention should be shifted to adults between 35 and 64 years old, among whom the suicide rate reached 17.6 deaths per 100,000 in 2010.

Here, 5 other key findings from the report:

Suicides outpace auto fatalities
There were more suicides than motor vehicle fatalities in 2009, a fact so shocking the CDC made that point in the second sentence of its report. According to the National Highway Traffic Safety Administration, there were 30,862 fatal crashes in 2009, well below the 36,909 suicides the CDC reported that year.

And while car-related deaths have dropped in every year since 2005, suicides have continued to rise.

"It may be time to change the benchmark for discussion of public health problems in the U.S.," says NPR's Scott Hensley. "For quite a while, the annual number of fatalities from auto accidents has been a kind of shorthand for health issues that are big and important."

Native Americans, men, more likely to commit suicide
The suicide rate among Alaska Natives and American Indians climbed a staggering 65.2 percent in the past decade, from 11.2 to 18.5 per 100,000 people. However, given that group's relatively small population, that amounted to just 171 total deaths in 2010.

While the suicide rate among women rose at a faster clip than that for men — 31.5 percent to 27.3 percent, respectively — men were still far more likely to commit suicide. The CDC reported 27.3 male suicides per 100,000, versus just 8.1 for women.

Economic factors likely drove the increase
The sluggish economy, which shed millions of jobs at the tail end of the study's window, was likely a key contributing factor to the incredible rise in suicides among middle-aged Americans. Suicide rates among other age groups less sensitive to economic volatility showed little change over the same period.

"The suicide rate started accelerating in 2008, 2009 and 2010 — someone might still be working, but their house is underwater, or they're working but they're working part-time,'' Eric Caine, the director of the CDC's Injury Control Research Center for Suicide Prevention, told BusinessWeek. "These things ripple into families. There's an economic stress."

Prescription-drug deaths have become more common
The wider availability of prescription drugs may also have contributed to the rise in the suicide rate. Suicides by poisoning, which includes drug overdoses, rose 24.4 percent since 1999, the second-largest increase of any suicide method.

It's not only that pharmaceuticals are more readily available to induce death — "abuse of the drugs helps put people in a frame of mind to attempt suicide by other means," Thomas Simon, one of the authors of the CDC report, told the Associated Press.

Guns are still most common method
Guns remained the leading method of suicide, comprising almost half of all such deaths. There were 10,393 firearm-related suicides in 2010, up from 7,634 a decade earlier.

Over the same time period, the rate of suffocation-induced suicides, which predominantly includes hangings, rose an eye-popping 81.3 percent, totaling nearly 5,000 in 2010 alone. That finding is particularly troublesome, the CDC report states, because "a large proportion of suicide attempts by suffocation result in death, suggesting a need for increased public awareness of suicide risk factors and research of potential suicide prevention strategies to reduce suffocation deaths."