Peter Lyman, a professor emeritus of the University of California, Berkeley’s School of Information who was known for his research on online information and social networks on the Internet, died July 2 at his home in Berkeley. He was 66.

For people who feel overwhelmed by information overload, research conducted by a team led by Lyman discovered some staggering numbers a few years ago to show why.

According to the widely cited study “How Much Information?,” worldwide information production increased at an average rate of 30 percent each year from 1999 to 2002.

The amount of new information stored on paper, film, optical and magnetic media doubled during those three years, the researchers reported. And, they said, if the supply of new material saved in 2002 alone were converted to print, it would fill half a million libraries the size of the Library of Congress.

“All of a sudden, almost every aspect of life around the world is being recorded and stored in some information format,” Lyman said in 2003. “That’s a real change in our human ecology.”

The intent of their study, Lyman told The Philadelphia Inquirer in 2004, “was to quantify people’s feelings of being overwhelmed by information and to look at trends. People had no sense of why this was happening or where the growth was.”

Among the study’s findings:

• About 92 percent of new information is stored on magnetic media, primarily hard drives.
• Although original information on paper continues to grow, most comes in the form of office documents and mail — not books, newspapers or journals.
• The United States produced about 40 percent of the world’s new stored information.

Varian said he “never realized the study would be so widely cited, but it kind of caught the public’s imagination.”

“We did (the study) basically to get some summer jobs for some of our students; nobody had pulled all this information together in one place,” his research partner and fellow UC Berkeley School of Information professor, Hal Varian, told the Los Angeles Times on Friday.

In 2005, Lyman became the director of the Digital Youth Project, a three-year study of how children use digital media in their everyday lives.

Lyman was born in San Francisco in 1940. He earned a bachelor’s degree in philosophy from Stanford University in 1962, and a doctorate in political science from Stanford in 1972.

After working at Michigan State University, he moved in 1987 to USC, where he founded the Center for Scholarly Technology, which established the university as a leader in library information systems..