limoncello. Fishing is another fundamental resource for Sicily. It has important tuna, sardine, swordfish and European anchovy fisheries. Mazara del Vallo is the largest fishing centre in Sicily and one of the most important in Italy. Industry and manufacturing Improvements in Sicily's road system have helped to promote industrial development. The region has three important industrial districts: Catania Industrial District, where there are several food industries and one of the best European electronics industry centres called Etna Valley (in honour of the best known Silicon Valley) which contains offices and factories of international companies such as STMicroelectronics and Numonyx; Syracuse Petrochemical District with chemical industries, oil refineries and important power stations (as the innovative Archimede combined cycle power plant); the latest Enna Industrial District in which there are food industries. In Palermo there are important shipyards (such as Fincantieri), mechanical factories of famous Italian companies as Ansaldo Breda, publishing and textile industries. Chemical industries are also in the Province of Messina (Milazzo) and in the Province of Caltanissetta (Gela). There are petroleum, natural gas and asphalt fields in the Southeast (mostly near Ragusa) and massive deposits of halite in Central Sicily. The Province of Trapani is one of the largest sea salt producers in Italy. Statistics GDP growth A table showing Sicily's different GDP (nominal and per capita) growth between 2000 and 2008: Economic sectors After the table which shows Sicily's GDP growth, this table shows the sectors of the Sicilian economy in 2006: Unemployment rate The unemployment rate stood at 21.5% in 2018 and was one of the highest in Italy and Europe. Transport Roads Highways have been built and expanded in the last four decades. The most prominent Sicilian roads are the motorways (known as ) in the north of the island. Much of the motorway network is elevated on pillars due to the island's mountainous terrain. Other main roads in Sicily are the Strade Statali, such as the SS.113 that connects Trapani to Messina (via Palermo), the SS.114 Messina-Syracuse (via Catania) and the SS.115 Syracuse-Trapani (via Ragusa, Gela and Agrigento). Railways The first railway in Sicily was opened in 1863 (Palermo-Bagheria) and today all of the Sicilian provinces are served by a network of railway services, linking to most major cities and towns; this service is operated by Trenitalia. Of the of railway tracks in use, over 60% has been electrified whilst the remaining are serviced by