http://successfulsoftware.net/2009/04/23/the-truth-about-conversion-ratios-for-software/

An anonymous survey of software vendors shows that the average sale to visit ratio is very close to the much quoted ?industry average? of 1%. However the data shows large variations between products and across different sectors (e.g. Windows vs Mac OS X).

The data set comprises a total of:

    8.1 million unique website visits
    2.2 million downloads
    110 thousand sales transactions