American students are worse at U.S. history than any other subject. This is not a new fact, but continues to be troubling, particularly for Kenneth Davis, author of "Don't Know Much About History: Everything You Need to Know About American History but Never Learned." The New York Times reports that only 12 percent of high school seniors demonstrated "proficiency" in U.S. history and 55 percent scored "below basic" in nationwide testing. In other words: we don't know our own history and haven't improved for the past two decades. Davis takes a closer look at the reasons behind this continued lack of historical knowledge.