XF 1.5 Big increase in Post Likes

According to the Statistics tool in the admin cp, there has been an exponential growth in Post Likes (we call them 'Thanks') on our forum over the past year. I assume there's some sort of abuse going on, it doesn't make sense that the forum would be averaging two Likes for every new post. How can I go about digging deeper into the statistics and tracking down the source of likes and discovering what's causing this bizarre situation?
I don't think there's a way to do that from the ACP, you're probably gonna have to dig in the SQL tables via phpmyadmin or similar.