I noticed that today, my Kindle books were reduced in price overall (including USA) and I discovered that it's because VAT had been reduced on ebooks from 15% to 3% with Amazon using a European loophole. I've readjusted the prices for my books to keep them at its old price (after VAT) but for anyone interested in reading and debating on this subject, follow the link below:
http://www.thebookseller.com/news/luxembourg-vat-move-could-lower-k...
Any other authors here who have Kindle books, you may need to double check your prices!