WASHINGTON — More than 20 years after the infamous Navy Tailhook scandal that awakened the public to sexual assault in military, too little has been done to reverse an epidemic of sexual violence within its ranks, lawmakers and sexual assault victims said on Capitol Hill on Wednesday.

And with last year’s scandal erupting at Joint Base San Antonio-Lackland’s Air Force’s sole Basic Training Center -- in which Air Force instructors allegedly preyed upon new recruits -- the public outcry for change has grown too loud to ignore. In response, the House Armed Services Committee held a hearing on the scandal Wednesday, after more than 78 members of Congress and about 15,000 people signed an online petition demanding hearings to get a full accounting of the scandal.

“I find it extremely disturbing that despite the collective work of Congress, the Department of Defense, the military services and the dedicated groups who advocate on the part of the victims of this heinous crime, sexual assault and sexual misconduct remains a problem within our Armed Forces,” said Committee Chairman Buck McKeon.

So far, at least 32 instructors have been investigated for rapes, sexual assaults, criminal offenses and other inappropriate relationships involving 59 female and male trainees at Lackland over the past three years.

Gen. Mark A. Welsh III, Air Force Chief of Staff, testified before Congress that in the wake of the scandal, the Air Force had completed six court-martial cases against military training instructors, all resulting in convictions, and two instructors received non-judicial punishment under Article 15 of the Uniform Code of Military Justice for having unprofessional relationships. Four more trials are scheduled, and 20 more instructors are under investigation, he said.

“We can’t accept this. It’s horrible,” he said. “But I don’t believe that it’s the entire Air Force that has this culture of sexual assault ... We have pockets of it,” he said, which the service was working to erradicate.

The absentee voting process has improved in recent years, but many service members and their families still face hurdles in casting their ballots, according to a new report from the Overseas Vote Foundation.

The foundation found that compared to overseas civilians, a higher percentage of military voters — 13.8 percent — tried to vote but could not finish the process, compared to 11.2 percent of civilians with the same problem, based on an OVF post-election survey of overseas citizens and military personnel and their family members, as well as local election officials.

But overall, there have been improvements in the voting experience for overseas military and citizen voters since the passage of the Military and Overseas Voter Empowerment Act in 2009. The 2012 election is the first presidential election and first full-fledged test of the impact of the MOVE Act.

“While we acknowledge the tremendous progress and positive trends now visible, continued improvements can still be realized,” the report stated.

More than one-fifth of military voters, 21.6 percent, did not receive their ballots, while 17 percent of overseas civilians did not receive them. That rate represents an improvement: 27.5 percent of military voters and 22 percent of civilian voters surveyed by OVF after the 2008 election didn’t get their ballots.

Military voters also were more likely than civilian voters to report getting their ballots late. Just over 4 percent of military voters got their ballots after Nov. 1, compared to 2.6 percent of civilian voters.