Tom may be referring to this link

"Twelfth-grade boys are nearly twice as likely to identify as conservative versus liberal, according to a respected federal survey of American youth.

In annual surveys over the last three years, roughly one-quarter of high school seniors self-identified as conservative or “very conservative” on the Monitoring the Future survey, a scholarly endeavor that dates to the 1970s. Only 13 percent of boys identified as liberal or very liberal in those years."

And while it is true that the numbers identifying as conservative has not been this high since the Carter years, it also shows that the majority identify as neither conservative nor liberal.