Salmonella and campylobacter caused the most reported bacterial foodborne illnesses in 2016, preliminary data recently released by the U.S. Centers for Disease Control and Prevention’s FoodNet program has found.

Although still one of the most common forms of foodborne illness, salmonella cases have dropped compared to previous years’ averages, according to the CDC.

Federal officials attribute stronger regulatory action in poultry production as a possible explanation for the decline

“We are making progress in detecting and responding more quickly to foodborne illness, but our priority remains preventing illnesses from happening in the first place,” said Food and Drug Administration director Susan Maybe in a statement.

Overall, FoodNet received reports of more than 24,000 illnesses, more than 5,500 hospitalizations and 98 deaths related to dangerous pathogens last year.

The number of actual cases typically far exceeds those that have been diagnosed, however.

There are no active salmonella or campylobacter outbreaks at this time.

Combined, salmonella and campylobacter have been responsible for about 15 percent of all foodborne illnesses outbreaks in the past two decades, a review of tracking data shows. Outbreaks for both have been most frequently reported in June.