The share of students borrowing money to pay for college increases year after year, and they’re borrowing more every year. Total student debt, adjusted for inflation, has tripled in just over a decade. The loan payments, which can be a few hundred dollars a month, take a big bite out of young adults’ still-low levels of disposable income. The debt makes them more prone to bankruptcy and lower homeownership rates. A key question is whether this pressing financial obligation might affect their preparation for a retirement that is several decades away. Here’s what researchers Matt Rutledge, Geoff Sanzenbacher, and Francis Vitagliano of the Center for Retirement Research learned about student debt: By age 30, the college graduates who are loan-free have saved…