Pypi (Cheeseshop) Score - derivation of ?

[shearichard]

Hi - Anyone know how the score offered by Pypi is derived ?

For instance in ...

http://pypi.python.org/pypi?%3Aaction=search&term=spam&submit=search

... 'bud.nospam 1.0.1' has a score of 9 but 'pydspam 1.1.9' has a
score of 7.

Where are those numbers from and what do they mean ?

Thanks


R.