SHANGHAI, Oct 27 (Reuters) - The value of China's yuan against its major trading partners fell to the weakest level in more than a year on Thursday, according to a Reuters calculation based on official data.

The CFETS index, a gauge that measures the yuan's strength against a basket of currencies, fell to 99.94 on Thursday, the lowest since Oct. 15, 2021, from 100.19 a day earlier.

The index has lost about 2.5% so far this year, while the yuan's spot value plunged 11.4% against a surging dollar during the same period. (Reporting by Winni Zhou, Jindong Zhang and Brenda Goh; Editing by Muralikumar Anantharaman)