I don't know if anyone else will find this of interest, but I like counting things.
Out of the 17,000 or so references that I have now collected, some 20% are available on the free(1) Internet. These include original texts, books, theses, journal articles and items in web sites. They are the full items, and not just bibliographic references
1. What I mean by 'free' is financially free (with 2 exceptions). This excludes depositories such as Project MUSE, JStor, paid-for services such as EEBO or Proquest, and publishers web sites where articles can cost from $35 upwards.
The two exceptions are ebrary, where it only costs a deposit of $5 to read books; and Ambix, where a £35 subscription to SHAC gives access to the (almost) complete backfile of Ambix.