SHANGHAI, Jan. 18 (Xinhua) -- The value of the Renminbi (RMB) yuan against the U.S. dollar hit a new high for the fourth straight day on Thursday with a central parity rate of 7.7758 yuan to the dollar, according to the Chinese Foreign Exchange Trade System.

    The central parity rate was 7.7938 yuan on Monday, 7.7895 yuan on Tuesday and 7.7798 on Wednesday.

    Thursday's exchange rate also marked a new high of 0.99634 yuan to the Hong Kong dollar.

    The value of the yuan overtook the HK dollar on Monday for the first time, with a central parity rate of 0.99945 yuan to one HK dollar. The central parity rate was 0.99698 yuan on Wednesday.

    The central parity rate against the euro hit a new high of 10.0592 yuan and the central parity rate against the British Pound was also a record at 15.3157 yuan.

    Insiders have ascribed the continuous appreciation of the RMB to China's growing trade surplus and foreign exchange reserves.

    The country's trade surplus last year soared 74 percent to a record 177.47 billion U.S. dollars.

    China's foreign exchange reserve reached 1.06 trillion U.S. dollars at the end of 2006, announced the People's Bank of China on Monday.

    The figure rose 30.22 percent over the end of 2005, exceeding one trillion U.S. dollars for the first time, according to the central bank.

    The RMB has risen by more than 4.3 percent since China's reform of the exchange rate system in July 2005, which allowed the yuan to float against the U.S. dollar within a daily 0.3 percent band from the official central parity rate.