More than six million vacationers, most of them from the continental U.S. or Japan, spend close to 11 billion dollars a year in this tropical archipelago. Defense, centered on U.S. military bases at Pearl Harbor, is the second largest moneymaker. Descendants of Asians, who immigrated in the 19th and early 20th century to work on sugar plantations, add to the mix of people in this only state with no ethnic majority: Caucasians constitute 24 percent; Japanese, 18 percent; Filipino, 12 percent. The remainder includes ethnic Chinese and those of Hawaiian ancestry. Ecologists estimate that 89 percent of Hawaii's flowering plants and 97 percent of its land animals—among them the world's only predatory caterpillars—exist nowhere else on Earth.