How many seven stars hotel given seven star?

Answer 1

None.

'Seven stars' is not an official classification for hotels.

It's purely marketing. After some hotels had called themselves 'six star' hotels (like a five star hotel, but supposedly even better), other hotels called themselves 'seven star hotels', but nobody has given them this title (and, essentially, there is nothing that keeps you from calling a run down hole in the woods a 'seven star hotel' - it's a meaningless term).