U.S. cases of the novel coronavirus were approaching 1 million on Tuesday, having doubled in 18 days, and made up one-third of all infections in the world. More than 56,000 Americans have died of the highly contagious respiratory illness COVID-19 caused by the virus, an average of about 2,000 a day this month. The actual number of cases is thought to be higher. About 30% of the cases have occurred in New York state, the epicenter of the U.S. outbreak, followed by New Jersey, Massachusetts, California and Pennsylvania. Globally, coronavirus cases top 3 million since the outbreak began in China late last year.