I have read about people posting about Tor sites that have the intent upon tracking users or attempting to find information. Is there any information about the proliferation of these types of 'spy' sites? Is the understanding (based on any known facts) that there are very few, far between Tor endpoints that do this or that there would be a large percentage based on the base of users? It is entirely possible that this is not possible to know, so I understand that, may be the answer regardless.
There are two particular matters that are worth separating. The first is whether it is possible for an adversary to locate you, or identify you, from things about your connection and use of Tor that are independent of the real content of your traffic. The second is whether an attacker can identify you from the content of the transmissions.
A good place to start to understand the issues is at the Electronic Frontier Foundation page on Tor and HTTPS, a page that separates the issues of privacy versus anonymity. Once you have read that page, and tried out the Tor and HTTPS buttons on the page to show the changes in the diagram, you might like to read this article, which explains how embassy officials misunderstood the difference between the anonymity that Tor provides and the secrecy/privacy that is provided by HTTPS.
Having looked at the EFF page, you might also like to read about jocularly-called “bad onions” which tamper with the Tor traffic in order to gain information about location of the user, rather than about content of the traffic.
At that point it might become apparent that your question appears to confuse, or at least not disentangle, the two separate problems … and a new question might be in order.
It is in my best understanding that this cannot be answered effectively due to the sheer anonymity of the way Tor is used. If anyone has any data I will gladly accept their answer, but for now I will call this one impossible to answer.