How much can click fraud affect Google's stock price and earnings?

Google's stock price has risen from an IPO price of 85 to 395 dollars. Investors have bid up the price of this company since its earnings are growing at an incredible pace. Google's earnings are mainly based on its Adwords program for its own search engine and its Adsense program for third-party websites. In its Adsense program, Google gives 60 percent of the cost per click program to the website owner. Click fraud occurs when a website owner, some one else, or an automated program clicks on the advertisements to increase earnings. How much could click fraud end up increasing Google's earnings? Although Google states it combats click fraud, some sources say it can account up to 20 percent of clicks. Even if it accounts for five percent of earnings, earnings generated from click fraud could account for GOOG's soaring stock price. Independent investigators should see if click fraud can affect Google's earnings, especially considering the market has given it a 100 billion dollar market value.