In 1946, the population was about 400,000; in 1997, it reached 4.6 million, a figure twice that of 1981. After the 1967 war with Israel and Iraq's 1990 invasion of Kuwait, there were sudden and massive influxes of Palestinian Arab refugees, who now make up more than two-thirds of the population. In 1996, 1,359,000 Palestinian refugees living in Jordan were registered with United Nations; 250,000 Palestinians continue to live in ten refugee camps. Nomadic people, predominantly Bedouin, account for more than 10 percent of the total population. The population is young, with a birthrate that is double the world average; 43 percent of the people are under age fifteen. By the year 2012, the population is expected to double.