Health officials say cruise ship passengers are getting sick with a stomach bug less often.
About 20 outbreaks are reported each year on ships that dock at U.S. ports, on average. Many draw media coverage.
But it's becoming less common for passengers to get sick, according to figures released Thursday by the Centers for Disease Control and Prevention.
Since 1990, the illness rate has fallen from about 29 to 22 per 100,000 passengers. Officials say cruise ship companies are doing more to disinfect ships and prevent outbreaks.
It wasn't a steady decline. Cases spiked in 2012 when a new strain of norovirus emerged. Norovirus causes most stomach illnesses on cruise ships.
In April, a cruise ship docked in San Diego with 95 passengers and 5 cruise members sickened by a stomach illness.
