Anna Mulrine reports that the Department of Defense is busy building a department-wide sexual assault database following the establishment (in 2005) of a "restricted reporting" system for victims that allows them not to report prosecutions. Almost 2,000 victims have come forward since the establishment of the system, though Dr. Kaye Whitley, the director of the Office of the Secretary of Defense's Sexual Assault Prevention and Response Office, notes that many of them tend not to proceed with prosecutions.
Whitley added that it is often difficult "to get victims to stay with the military criminal justice process." She noted that during testimony and investigations, they may have to "tell their story 25, 30 times, and it's very painful. And they drop out."
I would probably add that it's not the frequency of telling one's story that is painful, but the telling of it to people that act like you have some measure of culpability or who are cross-examining you about the details of it that is painful.
The Pentagon Takes Aim At Sexual Assaults [US News & World Report]