There is a worldwide shortage of this lens. I have heard that Nikon's explanation, beside it being a best seller, is that they have received orders direct from governments wishing to equip their police and security services and these orders are receiving priority.  

I will message you a place that does get some in from time to time.

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html