There are a lot of statistics store in the database, but they are not stored in an easy to get way. The table Event holds it all. The different EventTypes store different things. Some are at book level some at reader level. But, the data you are after is stored in a BLOB in some binary format. I can see roughly what is in some of them, but haven't bothered decoding them in full.
I have mapped out a lot of the EventTypes and posted them here a couple of times here. They do include counts, such as how many times a book has been opened or closed. That plus a total time read is all that is needed to calculate the time per session. But, the list of sessions does seem to be there.
If you want to see the stats for a book, you can add the following to the config file:
Code:
[FeatureSettings]
BookSpecificStats=true
With this, when you long-press on a book, it will have a statistics option in the menu. That will take you to the stats page for the book. Otherwise the stats page only shows the most current book.