I clicked at the botom end of the range. The majority of my dives (and hence the median dive if not the average dive) are a walk across the road and down the bank into the sea. Hence just the fill cost $NZ6 or about 2 pounds 30p..
If I factored my once annual overseas excursion - Solomon Islands in September 2008 in - the answer would be somewhat different but I can't do those maths in my head!
Alison