A long sojourn
If you want to know how many books are released, and where, check out the Go Hunting pages https://www.bookcrossing.com/hunt
In any case, welcome back!
but how big a thing?
And a third way to look at it is here: https://www.bookcrossing.com/about which shows the cumulative number of members who have registered (although most are not active) and the cumulative total of books that have been registered by them.
Or you could look at the Release Challenges forum to see how some members are currently releasing books. https://www.bookcrossing.com/---/23
And yet another way, a look at Meetings and Conventions currently taking place or being planned https://www.bookcrossing.com/---/22 so you can see that in some parts of the globe BookCrossers are still very interested in getting together with each other.
I am encouraging you to release another book soon. Being so melancholic you might not have any fun from this, maybe just sad to see a book go? Don't worry because someone else might have fun finding a book!
No, joking apart, get into it and you might soon have reason to change your name.