Undergraduate enrollments increased by more than a third, to 17.6 million, in the first decade of the 21st century, with the most dramatic growth occurring at for-profit colleges, a federal report out today shows. It was the fastest decade of growth since the 1970s. The for-profit higher education sector posted a number of highs ? and lows? in other findings, including the highest average price of attendance after grants are factored in, highest average loan amounts and the lowest spending per student on instruction, according to the report by the National Center for Education Statistics.