If Gran Turismo released every 2 years how much would each sell?

[Jaywood2010]

KingHades said:
GT5 Prologue is basically GT5.
Prologue is the Demo so GT5 has been passed 10mil.

That is an odd way of looking at it.  How many of those people who bought Prologue bought GT5?  That is why they are considered seperate, because they are seperate games.