In March the two countries struck a three-year $3.39 billion deal to produce liquefied natural gas in Iran's mammoth South Pars natural gas field. Because of its limited refining capacity, Iran imports one-third of its refined products such as petrol from China. In 2011, the group Green Experts of Iran reported that Beijing and Tehran had signed an extensive deal that would give China exclusive rights to several Iranian oil and natural gas fields through 2024. Under the terms of the deal, Iran will give Chinese oil companies exclusive rights to three large regions of Iranian land as well as the rights to build all necessary infrastructure for these regions, all of which sit atop of large oil and natural gas fields. In return, China promises to treat any foreign attack against these regions as attacks against its own sovereign territory, and will defend them as such. China will have no need for prior permission from the Iranian government to maintain and increase its military presence in Iran, and will control the movement of Iranians in and out of these territories. The Green Experts of Iran speculate that this agreement was the concrete basis for Major General Zhang Zhaozhong's statement that "China will not hesitate to protect Iran even with a third World War." China has been Iran's crude oil sink since the JCPOA was signed. In 2017, 64% of an export total $16.9 billion with China was labelled "crude oil". During the Cold War there were unofficial trade relations between Iran and China that have steadily increased over time. Trade reached $1.627 billion in the 1980s and $15 billion in 2007. In 2001, the volume of trade between Iran and China stood at roughly $3.3 billion, and in 2005, the volume of Sino-Iranian trade hit $9.2 billion. Iran's Deputy Minister of Commerce Mehdi Ghazanfari speculated that trade exchanges between Iran and China would exceed $25 billion in 2008. In 2005, exports from China represented 8.3% of the total import market in Iran, giving China the second largest share of the market after Germany. China's exports to Iran have experienced particularly rapid growth in the past five years, with China replacing Japan as the world's second largest exporter to Iran. Iran's imports from China rose by 360% between 2000 and 2005. China is now responsible for about 9.5% of all Iranian imports. In 1988, the Iranian market opened up to Chinese industry when the PRC began economic restructuring. Once profitable trade relations were established, the PRC invested in Tehran's subway systems, dams, fishery, and cement factories while Iran helped supply China with the highly desired minerals coal, zinc, lead, and copper.