what is the composition of the www in terms of filetypes?

[Super Nice Care Bears]

not html or any type of program or script, but rather in terms of downloadable filetypes.
do you think most of the downloadable or displayable *texts on web are .txt or .pdf? surely someone has published a study showing a pie chart of distribution? i am asking for text, so i can make use of the web better for studying, anyone can answer for video and sound etc., if they want
i have found filetype:pdf to be a very good search modifier on google as it gets me (more) professional documents quicker when i am searching.
exactly. i need a pie chart of most downloaded file types by category - video, sound, text, etc. thanks for the info btw.