was ranked 40th in the world by size. In 2016 a total of 39 Turkish construction and contracting companies were listed in the Top 250 International Contractors List prepared by the Engineering News-Record. Over half of Turkey's building stock contravenes housing regulations. An amnesty program to register illegal constructed buildings brought in $3.1 billion, but the safety issues largely remain. In mid-February 2019, an eight-story building that was registered in the amnesty collapsed killing 21 people. As Turkey is prone to strong earthquakes, poor building quality is even more concerning. Service sector Transport In 2013 there were ninety-eight airports in Turkey, including 22 international airports. , Istanbul Atatürk Airport is the 11th busiest airport in the world, serving 31,833,324 passengers between January and July 2014, according to Airports Council International. The new (third) international airport of Istanbul is planned to be the largest airport in the world, with a capacity to serve 150 million passengers per annum. The state-owned utility Turkish State Railways operates the 12,740–km railway network, 23rd longest in the world. Since 2003, Turkish State Railways has also been investing in high-speed rail lines, which at 2,175 km (1,353 mi) ranked ninth longest in the world. As of 2010, the country had a roadway network of 426,951 km, including 2,080 km of expressways and 16,784 km of divided highways. As of 2010, the Turkish merchant marine included 1,199 ships (604 registered at home), ranking 7th in the world. Turkey's coastline has 1,200 km of navigable waterways. In 2008, of natural gas pipelines and of petroleum pipelines spanned the country's territory. Communications As of 2008, there were 17,502,000 operational landline telephones in Turkey, which ranked 18th in the world; while there were 65,824,000 registered mobile phones in the country, which ranked 15th in the world during the same year. The largest landline telephone operator is Türk Telekom, which also owns TTNET, the largest internet service provider in Turkey. The largest mobile phone operators in the country are Turkcell, Vodafone Turkey, Avea and TTNET Mobil. The telecommunications liberalisation process started in 2004 after the creation of the Telecommunication Authority, and is still ongoing. Private sector companies operate in mobile telephony, long-distance telephony and Internet access. Additional digital exchanges are permitting a rapid increase in subscribers; the construction of a network of technologically advanced intercity trunk lines, using both fiber-optic cable and digital microwave radio relay, is facilitating communication between urban