China's annual average spending on overseas development projects showed "a dramatic expansion" to $85 billion in the five-year period from 2013, far outpacing the outlays by the United States, Japan and other major powers, a study by U.S. research lab AidData showed Tuesday.

The year 2013 is when Chinese President Xi Jinping advocated the Belt and Road Initiative to increase Beijing's influence abroad by financing and building infrastructure projects across Asia, Europe and Africa.

The report, which described Beijing's grant-giving and lending activities as "shrouded in secrecy," also revealed that Chinese development projects have been financed with debt rather than aid, and that most Chinese overseas lending is provided on less generous terms than from traditional bilateral and multilateral creditors.