Ah, thank you for the explanation. I digged around a little, and the base acceptance rate of all university applications was 54% för 2008. This is an aggregated number. For Sweden's most prestigeous med school (Karolinska Institutet) the number is 3,6%, so it does vary a lot depending on the education.
There are very few programmes that don't have any requirements. However, if one doesn't have any good high school grade, the "university entrance"-exam is a way in, or else professional experience. Hence, there are (again, depending on the education) a wider range of ages represented. However, 28% of all applicants are 19 years old. No one in my class is older than 25.
About universal and free, I'd say the system here is close to very good. According to me "universal" apply more to the possibility of actually studying, than the numbers of students accepted. And "free" is simply no tuition fees, which Sweden does not have. This is also the main difference, with the US having (large) fees.