Russian SFSR. During the Soviet era gas was exported mainly to other Soviet republics, as Turkmenistan steadily increased delivery from about 9.2 million m³ in 1940 to about 234 million m³ in 1960 and about 51 billion m³ in 1975. This export was under centralised control, and most of the export revenue was absorbed into the Soviet central budget. This changed in 1991, when Turkmenistan gained independence and established full control over gas export and export revenues. However, Soviet-era pipelines dictated that much of the gas go to the Caucasus, Russia and Ukraine. In the 1990s many of Turkmenistan's gas customers in the CIS failed to pay on time or negotiated barter deals. In the mid-1990s Turkmenistan stopped delivering gas to some CIS members, citing failure to pay and unprofitable barter deals. At the same time, the government tried to attract investments in building gas pipelines via Iran to Turkey and Western Europe via Afghanistan to Pakistan. Neither deal went through due to an unfavourable regional security environment and high costs; inflation and the budget deficit rose but privatisation was resisted. In the late 1990s the government renegotiated its export and price arrangements with Gazprom and renewed deliveries to Georgia, Ukraine, and some other countries. It also opened its first pipeline not to pass through Russia, the Korpezhe-Kurt Kui Pipeline. On December 14, 2009, the Central Asia–China gas pipeline was opened, and Turkmenistan began delivering large volumes of natural gas to the China National Petroleum Corporation. Combined design capacity of Lines A, B, and C of this pipeline system is 55 billion cubic meters per annum (bcma), of which Turkmenistan's quota is 35 bcma. By 2015 Turkmenistan was delivering approximately 35 bcma to China, counterbalancing declining exports to Russia, which ended on January 1, 2016. Russia had earlier restricted its imports to about 10 bcma, and then 5 bcma. Russian purchases resumed, albeit in smaller quantities, in 2019. Small-volume sales of an estimated 12 bcma to Iran halted on January 1, 2017, when Turkmenistan unilaterally cut off supplies over payment arrears. Ashgabat claimed Tehran owed some $1.8 billion for supplies delivered nearly 10 years before. In January–November 2020, Turkmenistan extracted 62.3 billion m3 of natural gas, of which, according to one source, it exported 31 billion. One observes in the table below that production and exports peaked in 2008 and dramatically decreased in 2009. This was due an explosion in