(CNN) -- More than 91 million Americans live in a county considered to have a "high" COVID-19 transmission. That's according to data published Tuesday by the Centers for Disease Control and Prevention.
That number is 18 million more than a day earlier.
The health agency says a county has "high" transmission if it has 100 or more positive cases per hundred thousand residents.
The number of people living in a county with "low" community transmission has been cut in half since early June. About 15 million people live in those areas.