I record total acidity against the wines in my database (when I am able to glean that information) and the figure is all over the place. It is as low as 5.7 grams per litre in something like the barrel fermented Cloudy Bay Te Koko 2002 and as high as 9 grams per litre in Lake Hayes Sauvignon Blanc 2004. The 'average', however, seems to be in the 7's (7.4 to 7.6).
So many factors come into play such as location, vintage conditions, when picked during vintage and so on.
Sauvignon Blanc changes so rapidly in the bottle and as the wine gets older, the acidity, while still there, does not seem to be so aggressive. Even in that early release Coopers Creek 2006, the acidity will settle in 2-3 months time, and then it will rate about 5 on the aggressiveness scale.