Saving "current place" of a book in a custom column

[TrulyInnovative]

I have a lot of books/fanfics that I'm reading at the same time, and often I don't remember how far along I am in each book. I love that the Calibre E-book viewer saves my current page as a bookmark, but I was wondering if there's any way to have that information available as a (custom) column in the main Calibre library view. This way, I could easily see how far along I am in each given book without having to open them manually. This information could be stored as a percentage, current page, or current chapter.

I don't know how feasible something like this is to implement, though. How easily could Calibre access this bookmark information?