SEOUL (AFP) - Parents in education-obsessed South Korea spent 19 trillion won (S$21 billion) on extra classes for their children last year, seeking any edge in the hugely competitive race for a coveted college place.

The 2012 figure, published by the education ministry on Wednesday, includes cost for after-hour cram schools, private tutoring or online courses, and was equivalent to about 1.5 per cent of the country's gross domestic product.

Last year actually marked a drop of 5.4 per cent in total spending from 2011, attributed to slowing economy and weakened consumer spending.

About 70 per cent of students in elementary, middle and high schools are privately tutored in subjects like mathematics or English, with annual spending for each student standing at an average US$2,600, the ministry said.

High marks in the national exam are essential for entry to top universities, which is in turn crucial to securing prestigious jobs or improving marriage prospects.

For most of their school lives, South Korean students study late into the night - often at costly, private cram schools - to stay ahead in the rat race for admission to top universities.