Amazon, where do my sales come from?

This post was inspired by Hugh Howey's recent blog post titled, "Stuff I Want to Know." (This isn't the first time that Mr. Howey has inspired me, by the way.) In the post, he lists 12 things that he would love to know from Amazon. Given his clout, I'm hoping that most of his questions will be answered.

One question that wasn't on his list, and that I asked in the comments (the only time my name will appear on a page written by Hugh Howey, I'm sure), was where my sales come from. I would love...