UNDATED (CNN) -- If you're looking for a career that leads to financial security, four years of college isn't the only path.

With college costs on the rise, more young people are beginning to question whether the cost of a four-year degree is worth it. A new study from Georgetown University could be part of that conversation.

According to the study, there are at least 29 million jobs for people without four year degrees. And at least a million are unfilled. These jobs, which range from areas like nursing to the trades, pay middle class wages.

The average is $42,000 a year and almost 40 percent of them pay salaries above $50,000. But there is one catch; most of these jobs still require you to get some sort of apprenticeship, training or post-secondary certificate. Those certifications can often be earned at community colleges or trade schools.

The most popular certificates for high school graduates include nursing assistant, commercial truck driver, and insurance agent. Popular certificates for those with associates' degrees include a licensed practical nurse, a paralegal or a coding specialist.

One of the study's authors says the existence of these well-paying jobs proves the middle class may be healthier than previously thought.