The National Bureau of Statistics (NBS) on Friday published China's innovation index, which shows that the nation's ability to innovate steadily improved between 2005 and 2011.

According to a method of measurement designed by an NBS research group, the China Innovation Index (CII) in 2011 reached 139.6, marking an average yearly growth of 5.7 percent from a base reading of 100 in 2005, said a statement on the NBS website.

Sub-indices that measure the country's innovation environment, input, output and effects show that China's performance in the respective dimensions of innovation all improved during the same period, the NBS said.

Guan Xiaojing, a senior analyst with the NBS research group, said the release of the index is a preliminary attempt to reflect China's innovation capability, and there is great room for improvement in terms of statistical methods.

Compared with other measurements, including the European Innovation Scoreboard, the CII is tailored more to China's current statistical system, Guan said.

The NBS also published a detailed description of its CII measurement on its website, welcoming comments and suggestions.