It probably won't come as any shock to college admissions officers or others who deal with traditional college-age students that high school seniors have changed significantly over the last 30-plus years. But some of the ways in which they have changed -- laid out in a new Education Department study Wednesday -- may challenge the conventional wisdom a bit.

The report, Trends Among High School Seniors, 1972-2004, examines -- yes -- demographic, attitudinal and other trends among high school seniors at four points over three decades. The demographic data provide little in the way of surprises; they show the high school-age population growing increasingly diverse over time, with white students making up 86 percent of the national high school senior class in 1972 and declining to 62 percent by 2004.

Black Americans showed the most social mobility over this period, with the proportion of African-American high school seniors who fell in the highest socioeconomic quartile rising to 13.5 from 5.2 percent while the proportion in the lowest quartile fell to 37.1 percent from 62.8 percent. The proportion of Asian Americans in the highest quartile rose to 30.9 percent from 23.1 percent, but the proportion in the lowest quartile increased slightly over that time span, too.

Although many faculty members like to complain about the declining capabilities of incoming students, the data show that students' have increasingly taken advanced courses in high school. The proportion of students enrolling in calculus increased to 13 percent in 2004 from 6 percent in 1982, while the percentage taking no math in the senior year fell to 34 percent from 57 percent. Twenty-five percent of seniors took advanced science courses (chemistry II, physics II or advanced biology) in 2004 compared to 12 percent in 1982, and the proportion not taking foreign languages as seniors fell to 76 percent from 87 percent.

Despite the popular perception that students are engaging in more activities (for resume padding if not out of enjoyment), the statistics suggest otherwise. While the report shows increasing numbers of high school seniors belonging to honor societies (22 percent in 2004 from 14 percent in 1972), the proportions participating in high school publications (19 percent in 1972, 16 percent in 2004), in vocational clubs (22 percent in 1972, 16 percent in 2004) and academic clubs (26 percent in 1972, 21 percent in 2004, even though the 2004 category was broader and included debate) all fell. Participation in athletics basically stayed flat, apart from a spike in 1980.

Perhaps the least surprising (but reasonably encouraging) data come in the area of the future expectations of high school seniors over time. Significantly greater proportions of seniors in 2004 said they planned to attend college (79.2 percent) and to attain a graduate or professional degree (38 percent) than was true in 1972 (59 and 13 percent, respectively).