求翻译：按照中国国家航空技术进出口总公司的预计，到2020年，中国至少需要10,000架直升机，这些飞机的市场总价值超过840亿美元。这是个乐观的估计，实际数字可能由于经济走势有所变化。但最保守的估计也表明到2013年，中国需要1,867架民用直升机，总价值49亿美元。是什么意思？

According to China National Aero-Technology Import and Export Corporation is expected that by 2020, China needs at least 10,000 helicopters, the total market value of these aircraft more than 84 billion U.S. dollars. This is an optimistic estimate, the actual figure may change due to economic trends

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According to the Chinese Country Aviation Technology Import and export Main corporation's estimate, to 2020, China needs 10,000 helicopters at least, these airplane market total value surpasses 84,000,000,000 US dollars.This is an optimistic estimate, actual numeral possible because the economical t

According to the China National Aero-technology import and export Corporation estimates that by 2020, China will need at least 10,000 helicopters, aircraft and total market value of more than $ 84 billion. This is an optimistic estimate of the actual figure may be due to changes in economic trends.

According to the expectation of the technological Import and Export Corporation of aviation of country of China, by 2020, China needs 10,000 helicopters at least, the market total value on these planes exceeds 84 billion dollars. This is an optimistic estimation, the real figure perhaps because the