The popularity of online education is rapidly expanding, according to a new report.

The report, titled “Learning on Demand: Online Education in the United States in 2009,” found that more than 4.6 million college students were taking at least one online course at the start of the 2008-2009 school year. That is a 17 percent increase from the previous academic year and means that one out of every four students is now pursuing a college degree from schools online.

The economic downturn may be responsible for fueling the growth of online education  and other distance learning degree programs, as they offer a convenient and inexpensive way for unemployed – as well as underemployed -workers to expand their skills and become more marketable in a tough job environment.

The survey’s authors also say that there is a lot of potential for online programs to expand further, especially at larger institutions.

“For the past several years, all of the growth – 90-plus percent – is coming from existing traditional schools that are growing their current offerings,” said the study’s co-author, Jeff Seaman.

According to US News and World Report, another study, by the Association of Public and Land-Grant Universities -Sloan Commission on Online Learning, indicated that faculty opinions regarding online education are improving as well. It reported that one-third of public university professors had taught online courses, and that more than half had recommended that students take classes online.