Industries that depend on copyright protection laws for their economic survival accounted for $819 billion of the U.S. economy last year, an industry lobbying group said Tuesday.

The economic contribution of "core copyright industries" in 2006 made up 6.6% of the U.S. gross domestic product, up from $760.5 billion, or 6.5%, in 2004, the International Intellectual Property Alliance said in a report released in Washington, D.C. Core industries include theatrical films, TV programs, home video, DVDs, business software, entertainment software, books, music, and sound recordings.

Those industries were responsible for almost 13% of the growth achieved in 2005 by the U.S. economy, said the alliance, which was joined by several lawmakers at a news conference. "What is clear from this and previous studies of the copyright industries is that their contribution to this country's economic growth continues to increase in size and importance," Eric H. Smith, a representative of the IIPA, said in a statement.

In releasing the report, the alliance is trying to make its case for tougher enforcement of copyright laws, and new legislation that takes into account changes in Internet technology.

"Copyright industries are uniquely dependent on governments' willingness to enforce good laws, particularly as globalization expands and Internet and broadband penetration escalates rapidly around the globe," Smith said. "Indeed, as our citizens and creators look to the great potential of a world of e-commerce, the legal and secure transmission of valuable copyrighted content over the Internet will be at the center of continued growth and productivity in the U.S. economy."

In hammering its point, the IIPA report found that core copyright industries last year employed slightly more than 4% of U.S. workers, or about 5.38 million people in 2005, which was slightly higher than in 2004. Foreign sales and exports reached $110.8 billion, topping the car, food, chemical, and pharmaceutical industries.