Despite increased awareness about the click-fraud situation and even despite lawsuits being filed because of it, click-fraud still remains a major problem for advertisers. In fact, it seems that the amount of click fraud is on the rise, now accounting for 14.1 percent of total hits. Click Forensics is the group that collected this data. For those who haven't heard about it, click fraud is essentially when an advertisement is clicked (usually automatically or at least intentionally) by a competing company or for a 3rd party looking only for click revenue. This, of course, isn't ever going to lead to a sale - wasting the money of whoever is paying for the advertisement. Some search companies, such as Google, consider the data behind the 14.1% rate to be flawed and say they have the situation under control:

Shuman Ghosemajumder, business product manager for trust and safety at Google, said the methodology of many click fraud reports, including that of the Click Forensics report, is flawed. For example, the survey does not take into account whether advertisers were charged for those fraudulent clicks, he said.
A spokesperson from Yahoo also responded, saying that it was "difficulty to comment" on the validity of the study. Regardless, click fraud does occur and is rather irksome to many, including the search companies behind the scenes.