BEIJING, July 24 (Xinhua) -- The gross domestic product (GDP) in China's western regions grew by 13.5 percent year on year in 2009, much higher than the country's revised national GDP growth of 9.1 percent, according to a report issued here on Saturday.

It is the eighth year in a row for these regions to score a double-digit GDP growth after the Chinese government launched a "West Development" campaign ten years ago, read the report on the economic development of China's western regions issued by the Chinese Academy of Social Sciences.

It attributed the GDP growth mainly to China's policies to stimulate domestic demand and the increase in investment, despite the global financial crisis.

Five provinces, regions or municipalities saw an increase of more then ten percent in the disposable income of urban citizens in 2009, as the income gap between China's western and eastern regions had begun to narrow, the report said.

The average yearly per capita disposable income of urban citizens in the western regions was 12,971 yuan (about 1,918 U.S. dollars) in 2008.

Noting that economic development in the western regions still heavily relied on natural resources, the report said efforts should be made to increase the regions' capacity to ensure sustainable development, while establishing a low-carbon industrial system.