BEIJING, May 15 -- A report released on Thursday showed that Chinese websites and computers were hit by numerous overseas attacks last year.

The China Internet Development Report 2014 jointly issued by the Internet Society of China and the China Internet Network Information Center said that "backdoors" created overseas hacked about 61,000 websites on the Chinese mainland last year, up 62.1 percent from 2012.

A backdoor is a method of bypassing normal authentication and securing illegal remote access to a computer.

Over 10.9 million computers on the mainland were controlled by overseas servers. The U.S. was home to 30.2 percent of these servers.