HSK: "Usual" scores required for each level

[yingguoguy]

At the weekend I got a set of sample papers for the HSK Basic exam and did the first one. Now if I've understood the marking system correctly the section score is not your percentage mark, but a scale mark based on your rank out of everyone taking the test. (Using 50% as the mean and then +-15% for each standard deviation) So in order assign myself a level (1,2 or 3) for that test, I'd need to know how everyone else did. Does anyone know either where I can get hold of the statistics for HSK results over the past few years, or else roughly where the boundaries are? Do they tend to vary a lot?

As an example on my sample test I got:

Grammar: 28/40

Vocab: 31/50

Listening: 26/50

Now obviously I'm hoping to bump these up in the next two months, but what could I expect to have got for this? I'm guessing borderline 1-2, but at the moment I really have no idea what the standard is.