How important is it to get the answer to something you’re idly curious about?
First most people do not know that every computer ever build has its own identification number. This is what they use to track you.
It is not just by using GOOGLE search engines.
Google owns (or has agreements with) many popular sites. They stick their cookies on your machine and then track where you go. These various sites exchange data and they add their own cookies.
Pretty much everything you do on line is tracked. Once they have you ... you can not get away.
True, but you can blur the focus to a level that makes it totally useless to them.
Install CCleaner, and have it clean after each browser session.