About 14.1 percent of clicks on text ad links are fraudulent, according to a new report scheduled to be released today from Click Forensics, the Associated Press reports. That's up from 13.7 percent three months ago. A recent report from Outsell estimated the proportion of fraudulent clicks at 14.6 percent.

Google and Yahoo are better at screening out click fraud than smaller players, according to Click Forensics, but some 12.8 percent of the clicks on Google and Yahoo ads are fraudulent, up from 12.1 percent three months ago, it says.

As click fraud more media attention, advertisers are demanding refunds and better protection, according to Tom Cuthbert, Click Forensics president. "They don't want to keep losing sleep at night wondering how much money they are losing to click fraud."