The director of the survey was surprised at the results...
“That almost one in five women have been raped in their lifetime is very striking and, I think, will be surprising to a lot of people,” said Linda C. Degutis, director of the National Center for Injury Prevention and Control at the Centers for Disease Control and Prevention, which conducted the survey.
“I don’t think we’ve really known that it was this prevalent in the population,” she said.
Which, really? It's fucking shitty but it surprises me that it surprises her. That's why it's important to do surveys like this because it's great to have real numbers, and to force people who might not be paying attention to realize what an endemic problem violence against women is, "even" here in a developed, relatively-wealthy, relatively-good-on-women's-rights country. But it's always interesting to see who takes the news with a "no shit" and who is like "these numbers are astounding!"
This AP article about sums it up:
Experts in domestic violence don't find it too surprising, although some aspects of the survey may have led to higher numbers than are sometimes reported.
Even so, a government official who oversaw the research called the results "astounding."