U.S. online job ads rose by 155,900 in June to a total of about 5.1 million, according to The Conference Board’s report on online jobs ads released today. The increase follows a loss of 18,900 job ads in May.

Last month’s supply/demand rate stood at two unemployed for every vacancy.

“The June increase of 155,900 is positive news. However, the net effect is that labor demand was basically flat for the first six months of 2014,” said June Shelp, vice president at The Conference Board. “There is churn in the labor market as people change jobs. Most of the gains since last June were in the lower-paying service jobs, not the higher-paying professional jobs.”

Since last June, employer demand has been down for the higher-paying professional jobs; ads for occupations like managers, business and finance workers, and computer workers all dropped. In contrast, ads increased for lower-paying jobs including transportation workers, office support, production workers, and construction.