The economy may still be in the tank, but overall college enrollments around the state managed to rise 3.6 percent this fall, buoyed largely by strong growth at two-year colleges. Housatonic Community College in Bridgeport is one of four community colleges that charted double-digit enrollment growth from fall 2008 to this year, according to enrollment figures released Friday by the state Department of Higher Education. This fall, HCC had 5,609 students, 528 more than last year, a 10.4 percent increase. Also marking significant jumps were Manchester, Middlesex and Three Rivers community colleges. Housatonic Registrar James Connelly said the economy definitely has something to do with the surge. It is far cheaper to attend a community college than a four-year school, while more people are returning to college for retraining after having lost their jobs. HCC has been able to offer more courses simply because it has more space. The school doubled in physical size last year when it opened a second building, Beacon Hall, alongside Lafayette Hall.