It goes up and down. It has been as high as 120-130Gb for the same download ; what you are downloading is the game plus updates that have been released since. Every so often this is consolidated into a new single download, hence it goes back to 100Gb or so, the default download size.
Also, the extra 13Gb or so is the standard free downloads that you download via the content manager, most of which is scenery stuff I think