US citizens or companies were at the center of most international intellectual property disputes heard in China in 2015 and 2016, according to the Supreme People's Court.

French and German were the next most common nationalities, the top court said in a report on Wednesday.

The SPC's work report in March said Chinese courts last year handled 147,000 IP cases involving foreign litigants or defendants. According to Wednesday's report, this was a 41 percent year-on-year rise.

More than half of cases were over copyright disputes, according to the report, which added that judges took on average 105 days to rule on IP cases, while patent disputes took longer.

Most cases in 2015 and 2016 were heard in Beijing as well as Guangdong and Zhejiang provinces, with more than 80 percent of defendants being private business owners, according to the report, which was compiled by the SPC's data center.