My data points for a UK centric app in the sports section of the app store (iPhone & iPad combined) :
#25 = ~ 20 sales/day
#15 = ~ 30 sales/day
#5 = ~ 50 sales/day
#3 = ~ 75 sales/day
So wildly different to US in terms of numbers - which is probably in itself unsurprising but great to see some actual numbers.
One thing I have noticed is that sales in general in the UK have gone up quite dramatically since Christmas - before Christmas we were in the top 10 of the Sports section of the UK app store and seeing around 20 - 25 sales a day - now you would be likely to see around 40 sales a day.