Google now enables an option in Google Account that saves all your queries and the results you clicked on. The service is called Web History and it can be extended to all the web pages you visit if you install Google Toolbar. In the screenshot, you can see the suggestions provided by Google after typing [gm] in the search box: there are 5 suggestions from my search history (all related to Gmail) and 5 popular queries from Google Suggest. Google doesn't provide a way to disable the suggestions from your search history, so your options are to log out, disable query suggestions from the preferences page or delete the web history.

Source:→ Google System