The enrollment boom that swelled U.S. higher-education institutions — and helped drive up their prices — is over, The New York Times reports. Signs point to 2013-14 as the beginning of a enrollment decline at traditional four-year, nonprofit colleges that will last for several years. The college-age population is dropping after more than a decade of growth, and many adults who went back to school during the recession have been drawn back to work by better economic conditions.