请将下面这段话翻译成英文：

2012年,中国在全球经济发展速度最快的国家中,名列第18位,GDP实际增速为7.8%。这是自1999年以来最慢的增速。但中国依然是成熟型经济的代表,因为中国正逐渐从发展中国家向发达国家过渡。自1949年以来,中国政府一直在规划和管理国民经济。1978年,邓小平引入资本主义市场原则（capitalist market principles)。从那时起,中国经济就开始展现出巨大的增长力。在过去30年间,中国的GDP以平均每年10%的速度在增长。这段时期,中国经济的规模增长了约48倍。

参考翻译

In 2012,China ranked the 18th fastest growing country in economy in the world, with a real GDP growth rate of 7.8 percent.The figure is the slowest one since 1999.However, China is also representative of a maturing economy as it is gradually transforming from a developing country to a developed one.Since 1949,the Chinese government has been planning and managing the national economy.In the year of 1978,Deng Xiaoping introduced capitalist market principles.From then on, the Chinese economy began to show massive growth.The GDP grew at the average rate of 10 percent annually over the last 30 years.During that period the scale of the Chinese economy grew by roughly 48 times.

1.成熟型经济的代表:“成熟型经济”可译为a maturing economy; “代表”可译为:representative。
2.过渡:可翻译为transform。
3.规划和管理国民经济:可译为plan and manage the national economy。
4.从那时起,中国经济就开始展现出巨大的增长力:“从那时起”可译为from then on。“巨大的增长力”可译为massive growth。