Twenty-five percent of working Americans hold an “alternative” post-secondary credential, which includes professional certifications, licenses and educational certificates, according to a U.S. Census Bureau report. In 2012, alternative credentials were most common among adults with an associate degree or higher, but more than 11 million adults with a high school diploma or less also held a professional certification or license.

The report also found people with an alternative post-secondary credential make more money per month than those without. The monthly median pay for full-time workers is $4,167 with only a professional certification or license; $3,920 with a professional certificate or license and an educational certificate; and $3,433 with only an educational certificate. The monthly median pay for people with no alternative credential is $3,110.