The number of international patent filings dropped last year for the first time since 1978 as companies hit by the global economic downturn sought fewer new protections on their intellectual property, the U.N. said Monday.

Most patents filed in 2009 were for computer technology, followed by pharmaceuticals and medical equipment. Innovations in computer chip design and nanotechnology saw the greatest rise in patents.

The World Intellectual Property Organization, or WIPO, received about 155,900 international patent filings last year, a drop of 4.5 percent compared with the nearly 164,000 filings received a year earlier.

Inventors in the United States still registered the highest number of international patents — 45,790, or almost a third of the total. But U.S. filings were down 11 percent compared with 2008.

Third-ranked Germany saw its patent filings drop by a similar amount to 16,736.

Asian inventors on the other hand increased their share and overall registrations, with Japan filing 29,827 international patent through WIPO. South Koreans registered 8,066 applications, just ahead of China's 7,946 filings — an increase of almost 30 percent year-on-year.

Japan's Panasonic Corp. was the company with the most patent filings, ahead of Huawei Technologies Co. of China and German firm Robert Bosch GmbH.

WIPO's annual patent figures are an important indicator of global IP protection efforts and therefore innovation.

For a fee, companies can file a request for patent protection in any or all of the 142 countries that have subscribed to the U.N.'s Patent Cooperation Treaty, avoiding the need to make individual filings in each country.

WIPO is the only United Nations agency whose income comes largely from services it provides to private industry, rather than contributions paid by member states.