Inventors at technology giant IBM led the nation in obtaining U.S. patents for the 21st consecutive year, according to a new survey.

IBM accounted for 6,809 patents in 2013, according to the tally by research firm IFI Claims Patent Services. The company significantly outpaced No. 2 Samsung, which racked up 4,675 patents.

A total of 660 of IBM’s patents originated at the company’s Research Triangle Park campus, one of the region’s largest employers.

“Our software team, in particular, is doing a lot of patent work there,” said IBM spokesman Michael Rowinski.

IBM was one of just three U.S.-based companies that ranked among the top ten. Microsoft was No. 5 and Qualcomm was No. 9.

The other seven top-ranked companies are headquartered in Korea, Japan and Taiwan. They include Canon, Sony, Panasonic and Toshiba.

More than 8,000 IBM employees contributed to its patents last year.