By Larry Swisher

The 25.5 percent of U.S. workers who hold a professional certification or license have higher earnings than those who don’t among all education levels, according to figures released April 15 for the first time by the Labor Department.

The new data come from questions added in 2015 to a monthly survey of 60,000 households, which is used to determine the unemployment rate.

“While BLS has published statistics on labor force status by level of education for a long time, nondegree credentials, such as professional certifications or licenses, have received less attention in national surveys,” Erica Groshen, commissioner of the Bureau of Labor Statistics, said in a statement posted on the agency’s website.

The new data will allow the BLS to see whether the proportion of people with certifications and licenses changes over time and to track “measures of labor market success for people who hold a certification or license, compared with people who don’t hold these credentials,” Groshen said.

Certifications and licenses—gained to demonstrate a worker has the skill or knowledge needed to do a specific job—include commercial driver’s licenses, teaching licenses, medical licenses and information technology certifications. Some occupations such as those in health care have more workers who hold certifications and licenses.

Among all full-time workers age 25 and older, median weekly earnings of workers with a certification or license were 34 percent higher than those without the credentials in 2015 ($1,004 versus $747).

The amount of the earnings premium varied by education. Weekly earnings of workers with some college or an associate degree and a certification or license were 11 percent higher than their peers who did not have the credentials ($825 per week versus $742).

The occupations with the highest proportions of workers who have a certification or license are health-care practitioners and technical (76.9 percent), legal (68.1 percent), and education, training and library (55.5 percent).

Government workers, many of whom are employed in education and health services, are more likely to hold a certification or license than private-industry workers (40.6 percent versus 22.6 percent).