World Openness Index, which gauged the openness level of 129 major economies from 2008 to 2019, was released Friday at the fourth Hongqiao International Economic Forum in Shanghai.

The index, compiled by the Institute of World Economics and Politics under the Chinese Academy of Social Sciences and the Research Center for Hongqiao International Economic Forum, was included in the World Openness Report 2021.

The 10 most open economies in 2019 were Singapore, Germany, China's Hong Kong Special Administrative Region, Ireland, the United Kingdom, Switzerland, the Netherlands, France, Canada, and Malta, according to the index.

Though around 80 percent of economies saw their level of openness expand, the global index declined from 0.7790 to 0.7480, or around 4 percent, from 2008 to 2019.

The United States, which was the most open economy in 2008, slid down to the 22nd position, with its openness index dropping to 0.7666 from 0.9328.

As the United States accounts for about 25 percent of the world economy, the country has dragged down the regional and global pace of cross-border opening up, the report noted.

The continual expansion of openness of China has raised the country's index ranking from the 62nd in 2008 to the 40th in 2019, up 22 places and reaching 0.7420, showed the index report.

China has rolled out a slew of concrete measures in opening-up, including promoting joint efforts to build the Belt and Road, establishing pilot free trade zones, and hosting the China International Import Expo. These actions have effectively eased the momentum of shrinking global openness, stated the report.

The world still has a great potential for openness, and expanding openness is in the common interest of mankind, the report concluded.