These are the first two articles I found after I Googled "rape women military statistics":
The private war of women soldiers
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I have talked to more than 20 female veterans of the Iraq war in the past few months, interviewing them for up to 10 hours each for a book I am writing on the topic, and every one of them said the danger of rape by other soldiers is so widely recognized in Iraq that their officers routinely told them not to go to the latrines or showers without another woman for protection.
The female soldiers who were at Camp Arifjan in Kuwait, for example, where U.S. troops go to demobilize, told me they were warned not to go out at night alone.
"They call Camp Arifjan 'generator city' because it's so loud with generators that even if a woman screams she can't be heard," said Abbie Pickett, 24, a specialist with the 229th Combat Support Engineering Company who spent 15 months in Iraq from 2004-05. Yet, she points out, this is a base, where soldiers are supposed to be safe.
Spc. Mickiela Montoya, 21, who was in Iraq with the National Guard in 2005, took to carrying a knife with her at all times. "The knife wasn't for the Iraqis," she told me. "It was for the guys on my own side."
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http://www.salon.com/news/feature/2007/03/07/women_in_military/____________________
Report: Sexual assault of women soldiers on rise in US military
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Although no comprehensive statistics have been compiled on the number of women soldiers raped in Iraq, rumors of the problem were so prevalent that in 2004 then-Secretary of Defense Donald Rumsfeld created a task force to look into the issue. Although the findings were never released publicly, the military created a website to deal with potential sexual assault in the military and also initiated classes on preventing sexual assault and harassment. The number of reported military assaults rose from 1700 in 2004 to more than 2300 in 2005.
But Benedict says, as with most sexual assaults, the actual number is vastly underreported. This situation in Iraq is compounded because often those committing sexual assaults are senior officers or members of a woman's unit. There is also the problem of widespread availability of hard-core pornography on US military bases in Iraq, which helps create an atmosphere of sexual tension. Women who have reported sexual assaults, Benedict alleges, have often been ignored or treated as pariahs by fellow soldiers. Also, as she points out in the Salon article, there's a long history of such allegations.
Rape, sexual assault and harassment are nothing new to the military. They were a serious problem for the Women's Army Corps in Vietnam, and the rapes and sexual hounding of Navy women at Tailhook in 1991 and of Army women at Aberdeen in 1996 became national news. A 2003 survey of female veterans from Vietnam through the first Gulf War found that 30 percent said they were raped in the military. A 2004 study of veterans from Vietnam and all the wars since, who were seeking help for post-traumatic stress disorder, found that 71 percent of the women said they were sexually assaulted or raped while in the military. And in a third study, conducted in 1992-93 with female veterans of the Gulf War and earlier wars, 90 percent said they had been sexually harassed in the military, which means anything from being pressured for sex to being relentlessly teased and stared at.
In Iraq, the problem has allegedly grown worse. Col. Janis Karpinski (who was demoted from brigadier general for her role in the Abu Ghraib scandal) alleged last year that three women died of dehydration in 2003 because they were afraid to go to the latrines at night for fear of being sexually assaulted, and so did not drink any water late in the day. The Army calls the charges "unsubstantiated." Colonel Karpinski, however, is sticking to her charges.
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http://www.csmonitor.com/2007/0319/p99s01-duts.html