Suspect that you use Google a lot? If you're logged in to your Google account, you can use its web history feature to track how often you search and see a record of what you've been up to.
Visit the web history page and you can see a colour-coded calendar showing your search habits. (Google may try to persuade you to install its toolbar, but you can skip that option.) If you don't like the idea of Google tracking your activity at that level, you can permanently switch it off.