NEW YORK -- More than 33 million people have used mobile phones to access the Internet this year, according to Nielsen Media Research, which Wednesday announced its new effort to measure such use.

With Nielsen known primarily for its ratings system for television viewing, the announcement is another indication of how it is trying to keep up with rapidly changing entertainment options.

At first, Nielsen is simply offering information culled from interviews of the 30,000 people included in its television sample. Besides the people who have used their phones for Internet access, Nielsen estimated that 8 million people viewed video on their phones during the first three months of the year.

One-quarter of all people aged 18 to 34 use their phones to access the Internet, Nielsen said.

The mobile video audience actually skews older and male: nearly half (46 percent) of this audience is aged 35 and up, and 54 percent are men, Nielsen said.

Nielsen is still unable to specifically measure what videos are hottest on cell phones. The company is working to develop technology that would accomplish this, either through a tiny meter attached to a phone or a docking station that can record how the phone was used, said Karen Gyimesi, company spokeswoman.