immediately after Iceland in 2080. Nonetheless, the overall population estimate has remained relatively stable because of a considerable immigration flow, mainly from the Italian mainland, but also from Eastern Europe (esp. Romania), Africa and Asia. Life expectancy Average life expectancy is slightly over 82 years (85 for women and 79.7 for men). Sardinia shares with the Japanese island of Okinawa the highest rate of centenarians in the world (22 centenarians/100,000 inhabitants). Sardinia is the first discovered Blue Zone, a demographic and/or geographic area in the world with an oversize concentration of centenarians and supercentenarians. Foreign immigration In 2016 there were 50,346 foreign national residents, forming 3% of the total Sardinian population. The most represented nationalities were: 13,995 4,470 4,319 3,259 2,391 1,865 1,599 1,361 1,198 1,136 1,113 694 669 642 621 Main cities and Functional Urban Areas Sardinia's most populated cities are Cagliari and Sassari. The Metropolitan City of Cagliari has 431,302 inhabitants, or about ¼ of the population of the entire island. Eurostat has identified in Sardinia two Functional Urban Areas: Cagliari, with 477,000 inhabitants, and Sassari, with 222,000 inhabitants. Government and politics Sardinia is one of the five Italian autonomous regions, along with the Aosta Valley, Trentino-Alto Adige/Südtirol, Friuli Venezia Giulia and Sicily. Its particular statute, which in itself is a constitutional law, gives the region a limited degree of autonomy, entailing the right to carry out the administrative functions of the local body and to create its own laws in a strictly defined number of domains. The regional administration is constituted by three authorities: the Regional Council (legislative power) the Regional Junta (executive power) the President (chief of executive power) Administrative divisions Since 2016, Sardinia is divided into four provinces (Nuoro, Oristano, Sassari, South Sardinia) and the metropolitan city of Cagliari. Military installations Around 60% of all the military installations in Italy are in Sardinia, whose area is less than one-tenth of all the Italian territory and whose population is little more than the 2,5%. The island hosts in fact NATO joint forces and Israeli military forces, which use the island's territory to simulate war games; the Inter-service Test and Training Range of Salto di Quirra (PISQ) is one of the most important experimental military training centres in Europe. The bases, used for manufacturing plants and military testing grounds, totally take up more than 350 km2 of the island's land, making Sardinia the most militarized region in