(Businessweek) — Women with engineering or computer science degrees often disappear just as they are within grasp of reaching career peaks. Of the top 100 tech companies in 2008, women accounted for a mere 6 percent of chief executives, according to the National Center for Women and Information Technology. Of companies that raised venture capital in 2006, not even 7 percent were founded by women. Meanwhile the number of startups led by female chief executives that attracted funding last year was just 4.3 percent, according to VentureOne, a venture-investment tracker. As distressing as such facts are for the U.S. technology field, there is another, far-more-alarming number: Only 18 percent of college graduates with computer science degrees in 2008 were women—down from 37 percent in 1985, according to NCWIT.