Young women and mature students are among the most likely people to drop out of university, a survey has revealed.

Yet dyslexic students or those from ethnic minority backgrounds are more likely to complete their studies.

The surprising findings emerged in a study commissioned by the University of Sussex to look at drop out rates since 2002.

Mature students, aged 21 or over when their courses began, account for a third of undergraduate drop outs at the University of Sussex. While about 10% of mature students will quit before the end of the first year compared with just 5% of under 21s.

Of the mature students surveyed, 30% said they quit for "other" reasons while 28% cited academic difficulties as their reason for leaving.

Among under 21s the most popular reason for leaving was given as "other", closely followed by "transport" and "personal reasons".

The study suggests that financial difficulties were a background factor for drop outs, though few students admitted it.

It hints the other most likely groups to drop out of university altogether were science students and candidates from a family with parents working in unskilled manual labour.

Subjects in which students were most likely to quit included Art History, Music, Science Technology and Sociology.

From 2006 to 2007, 3.6% of arts students dropped out compared with almost twice that amount with 6% in the sciences. Altogether, the University of Sussex saw a drop out rate of 4.4% that year.

This is well clear of the national average, which suggests 20% of all students studying undergraduate degrees were likely to quit.

With tuition fees reaching the £3,000 per year threshold, critics have suggested the increased costs of studying could signal a new surge of students quitting university. But figures from the same university ten years ago, before Labour introduced fees, suggest otherwise.

They actually show drop out levels were higher at an average 20 % for the year.

Dropping out of university is by no means a sign of failure. In the US there are famous examples of people who have not completed university but found success including Harvard dropouts Bill Gates and Facebook creator Mark Zuckerberg.