The demand for patents is increasing, with applications for patents doubling in the last 20 years, the UN intellectual property agency said on Monday.

The World Intellectual Property Organization (WIPO), a UN agency, reported that 5.4 million patents were in effect in 2004. The WIPO said the steady growth indicated growing economic activity around the world.

The findings are the result of improvements in the “collection and analysis of patent data” by the agency, Kamil Idris, the director general of WIPO said.

In 1985, nearly 885,000 applications were filed, compared to nearly 1.6 million in 2004.

Since 1995, the number of applications has risen at 4.75 percent, a figure in line with the average annual growth in the global gross domestic product (GDP) at 5.6 percent.

The top five patent offices according to the total number of patent filings in 2004 were, from highest to lowest: Japan, USA, South Korea, China and the European Patent Office. The patents in those offices accounted for 75 percent of all patents filed worldwide.