The gross domestic product (GDP) of the 16 cities in the Yangtze River Delta grew by 16.4 percent last year to nearly 4 trillion yuan, according to the Yangtze River delta research center under the Jiangsu provincial bureau of statistics.

The GDP of the 16 cities stood at 3.9526 trillion yuan accounting for 18.9 percent of China's total, which means these cities continued to act as a major force in the country's economy growth, the research center said in a report.

Shanghai, with a GDP of 1.03 trillion yuan, the first time the city's GDP has exceeded one trillion yuan, topped the 16 cities. The eight cities in Jiangsu Province recorded more than 1.7 trillion yuan and the seven cities in Zhejiang Province over 1.1 trillion yuan.

Besides Shanghai, Suzhou, Hangzhou, Wuxi, Ningbo and Nanjing all registered a GDP above 200 billion yuan last year.