Chain restaurants have slightly cut down on the amount of sodium they are using but a new report suggests that progress is slow and inconsistent. The nonprofit Center for Science in the Public Interest reveals that a review of 136 meals from 17 top restaurant chains indicates that the companies have generally reduced sodium by an average of six percent between 2009 and 2013, or roughly 1.5 percent each year.

According to the review, Subway, Burger King, and McDonald’s had the biggest reductions in sodium. However, in the reviewed meal samples, KFC and Jack in the Box increased their sodium amounts by 12.4 percent and 7.2 percent, respectively.

Although progress is reported, 79 percent of 81 adult meals in the study had over 1,500 milligrams of sodium. The study suggests that most Americans, including those aged 51 and over, individuals with high blood pressure, and African Americans, attempt to limit their sodium intake to 1,500 mg per day, as is suggested by the Centers for Disease Control and Prevention.

Michael F. Jacobson, executive director of CSPI, said in a statement, “For far too long, the FDA has relied on a voluntary, wait-and-see approach when it comes to reducing sodium in packaged and restaurant food.” Jacobson continued, “If chains like KFC, Jack in the Box, and Red Lobster are actually raising sodium levels in some meals, FDA’s current approach clearly isn’t working.”