Over the past 15 years, most OECD economies have experienced a large increase in the number of students in higher education, reaching over 30% in 10 of the 19 countries studied. The absolute number of students in S&T fields shows an overall increase too, but the proportion of S&T students has steadily decreased during the same period. Some disciplines do better than others. Engineering students account for 40% to 60% of S&T students in most countries, especially at the new tertiary entrant and graduate levels, and are characterised by a stable or positive enrolment trend over the past 10 years. The situation for physical sciences and mathematics is the opposite, where a decline is often seen in the absolute number of students, and the proportion of students in such fields was actually halved between 1995 and 2003. On the other hand, the proportion of students in the life sciences has remained mostly stable, due primarily to an increasing number of female students. The number of computer science students has increased dramatically, perhaps as a consequence of shifts in student choice within the overall domain of S&T.