The collegeboard has the data in a nice chart on their site showing the distribution of students who attend schools by the published tuition & fees rates :
Distribution of Full-Time Undergraduates by Tuition and Fees
Full time undergrads go to universities with a median published tuition & fee rate of $11,093.
Pubic schools median is $9,011 and private nonprofit is $31,290. Most students go to public schools so the overall median is much closer to the public school rate than the higher private school cost.
About 2/3 of students go to schools with rates below $18,000 and 81.9% are at schools charging under $30,000.
88% of public university students are at schools that cost UNDER $18,000. 84% of students are in private schools that cost OVER $18,000
The vast majority of public universities charge under $18,000 and the vast majority of private universities charge over $18,000.
Keep in mind that these are the published tuition and fee rates and that most students also receive financial aid of some form so the actual net cost to students is less.
While the average tuition at public schools is $8,890 in the '13-'14 school year the NET paid amount is just $3,120. For profit schools the average was $30,090 and the net was $12,460. You can find the net pricing in the college board trends in college pricing data. Specifically see Fig. 10 and Fig. 11 in the XLS data.
In 2012 the average student aid in grants was about $7,200 and tax benefits averaged $1200. See college board info on trends in student aid.
Of course this figure is an average while the other figure is a median. And aid will be weighted at the lower income group. So the two figures don't really match.
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