A staggering 45 percent of the 1.6 million veterans from the wars in Iraq and Afghanistan are now seeking compensation for injuries they say are service-related. That is more than double the estimate of 21 percent who filed such claims after the Gulf War in the early 1990s, top government officials told The Associated Press.

What's more, these new veterans are claiming eight to nine ailments on average, and the most recent ones over the last year are claiming 11 to 14. By comparison, Vietnam veterans are currently receiving compensation for fewer than four, on average, and those from World War II and Korea, just two.

It's unclear how much worse off these new veterans are than their predecessors. Many factors are driving the dramatic increase in claims — the weak economy, more troops surviving wounds, and more awareness of problems such as concussions and PTSD. Almost one-third have been granted disability so far.

Government officials and some veterans' advocates say that veterans who might have been able to work with certain disabilities may be more inclined to seek benefits now because they lost jobs or can't find any. Aggressive outreach and advocacy efforts also have brought more veterans into the system, which must evaluate each claim to see if it is war-related. Payments range from $127 a month for a 10 percent disability to $2,769 for a full one.

As the nation commemorates the more than 6,400 troops who died in post-9/11 wars, the problems of those who survived also draw attention. These new veterans are seeking a level of help the government did not anticipate, and for which there is no special fund set aside to pay.

The Department of Veterans Affairs is mired in backlogged claims, but "our mission is to take care of whatever the population is," said Allison Hickey, the VA's undersecretary for benefits. "We want them to have what their entitlement is."

The 21 percent who filed claims in previous wars is Hickey's estimate of an average for Operation Desert Storm and Desert Shield. The VA has details only on the current disability claims being paid to veterans of each war.

The AP spent three months reviewing records and talking with doctors, government officials and former troops to take stock of the new veterans. They are different in many ways from those who fought before them.

More are from the Reserves and National Guard — 28 percent of those filing disability claims — rather than career military. Reserves and National Guard made up a greater percentage of troops in these wars than they did in previous ones. About 31 percent of Guard/Reserve new veterans have filed claims compared to 56 percent of career military ones.

More of the new veterans are women, accounting for 12 percent of those who have sought care through the VA. Women also served in greater numbers in these wars than in the past. Some female veterans are claiming PTSD due to military sexual trauma — a new challenge from a disability rating standpoint, Hickey said.

The new veterans have different types of injuries than previous veterans did. That's partly because improvised bombs have been the main weapon and because body armor and improved battlefield care allowed many of them to survive wounds that in past wars proved fatal.

"They're being kept alive at unprecedented rates," said Dr. David Cifu, the VA's medical rehabilitation chief. More than 95 percent of troops wounded in Iraq and Afghanistan have survived.

Larry Bailey II is an example. After tripping a rooftop bomb in Afghanistan last June, the 26-year-old Marine remembers flying into the air, then fellow troops attending to him.

"I pretty much knew that my legs were gone. My left hand, from what I remember I still had three fingers on it," although they didn't seem right, Bailey said. "I looked a few times but then they told me to stop looking." Bailey, who is from Zion, Ill., north of Chicago, ended up a triple amputee and expects to get a hand transplant this summer.

He is still transitioning from active duty and is not yet a veteran. Just over half of Iraq and Afghanistan veterans eligible for VA care have used it so far.

Of those who have sought VA care:

—More than 1,600 of them lost a limb; many others lost fingers or toes.

—At least 156 are blind, and thousands of others have impaired vision.

—More than 177,000 have hearing loss, and more than 350,000 report tinnitus — noise or ringing in the ears.

—Thousands are disfigured, as many as 200 of them so badly that they may need face transplants. One-quarter of battlefield injuries requiring evacuation included wounds to the face or jaw, one study found.

"The numbers are pretty staggering," said Dr. Bohdan Pomahac, a surgeon at Brigham and Women's Hospital in Boston who has done four face transplants on non-military patients and expects to start doing them soon on veterans.

Others have invisible wounds. More than 400,000 of these new veterans have been treated by the VA for a mental health problem, most commonly, PTSD.

Tens of thousands of veterans suffered traumatic brain injury, or TBI — mostly mild concussions from bomb blasts — and doctors don't know what's in store for them long-term. Cifu, of the VA, said that roughly 20 percent of active duty troops suffered concussions, but only one-third of them have symptoms lasting beyond a few months.

That's still a big number, and "it's very rare that someone has just a single concussion," said David Hovda, director of the UCLA Brain Injury Research Center. Suffering multiple concussions, or one soon after another, raises the risk of long-term problems. A brain injury also makes the brain more susceptible to PTSD, he said.

On a more mundane level, many new veterans have back, shoulder and knee problems, aggravated by carrying heavy packs and wearing the body armor that helped keep them alive. One recent study found that 19 percent required orthopedic surgery consultations and 4 percent needed surgery after returning from combat.

All of this adds up to more disability claims, which for years have been coming in faster than the government can handle them. The average wait to get a new one processed grows longer each month and is now about eight months — time that a frustrated, injured veteran might spend with no income.

More than 560,000 veterans from all wars currently have claims that are backlogged — older than 125 days.

The VA's benefits chief, Hickey, gave these reasons:

—Sheer volume. Disability claims from all veterans soared from 888,000 in 2008 to 1.3 million in 2011. Last year's included more than 230,000 new claims from Vietnam veterans and their survivors because of a change in what conditions can be considered related to Agent Orange exposure. Those complex, 50-year-old cases took more than a third of available staff, she said.

—High number of ailments per claim. When a veteran claims 11 to 14 problems, each one requires "due diligence" — a medical evaluation and proof that it is service-related, Hickey said.

—A new mandate to handle the oldest cases first. Because these tend to be the most complex, they have monopolized staff and pushed up average processing time on new claims, she said.

—Outmoded systems. The VA is streamlining and going to electronic records, but for now, "We have 4.4 million case files sitting around 56 regional offices that we have to work with; that slows us down significantly," Hickey said.

Barry Jesinoski, executive director of Disabled American Veterans, called Hickey's efforts "commendable," but said: "The VA has a long way to go" to meet veterans' needs. Even before the surge in Agent Orange cases, VA officials "were already at a place that was unacceptable" on backlogged claims, he said.

He and VA officials agree that the economy is motivating some claims. His group helps veterans file them, and he said that sometimes when veterans come in, "We'll say, 'Is your back worse?' and they'll say, 'No, I just lost my job.'"

Jesinoski does believe these veterans have more mental problems, especially from multiple deployments.

"You just can't keep sending people into war five, six or seven times and expect that they're going to come home just fine," he said.

For taxpayers, the ordeal is just beginning. With any war, the cost of caring for veterans rises for several decades and peaks 30 to 40 years later, when diseases of aging are more common, said Harvard economist Linda Bilmes. She estimates the health care and disability costs of the recent wars at $600 billion to $900 billion.

"This is a huge number and there's no money set aside," she said. "Unless we take steps now into some kind of fund that will grow over time, it's very plausible many people will feel we can't afford these benefits we overpromised."

How would that play to these veterans, who all volunteered and now expect the government to keep its end of the bargain?

"The deal was, if you get wounded, we're going to supply this level of support," Bilmes said. Right now, "there's a lot of sympathy and a lot of people want to help. But memories are short and times change."

Online:

VA's Home Page | VA budget, performance | IOM Coming Home report | Costs of war | Veterans quick fact | War casualty reports  | Brain Injury Center