Board Thread:Lore Discussion/@comment-24079263-20131112030749/@comment-24081142-20131112233830

Do you mean, how many actually appear in-game? Or how many exist in total in the whole of Nirn?

If the latter, nobody knows because it is impossible to count them in any meaningful way (a book refers to an attempt to catalogue them.  The scrolls are counted.  Then one is removed, but when they are re-counted, there are more than before.)  They violate the laws of physics and causality, moving apparently at random through space and time, and generally misbehaving.