Educational borrowing is up for every age group over the past three years, but it has grown far more quickly among those between 35 and 49, according to the analysis of more than 3 million credit reports provided to Reuters by the credit score tracking site CreditKarma (CreditKarma.com). That group saw its school debt burden increase by a staggering 47 percent, according to the analysis. The average student loan debt for those aged 38 to 41 was the biggest of that group -- about $12,000, up from just under $9,000 in 2009. Young people still carry the biggest student loan burdens; those aged 26 to 29 have an average of $14,000 in student debt. But the increased levels in middle-aged student debt is a new phenomenon.