There is no single page showing percentages presently as it's impossible to be remotely accurate, other than when very close to the end or when a fixed and defined work unit set makes up the research. That said, someone of WCG is constantly working on improving the science project information and making it more accessible. For now, can only refer to the links on the Research pages. Till then, the closest of an overview in guesstimates of % and end dates, as good as they come, is in the Graphs link below... very fluid with 9 sciences concurrently running and all competing, if they do, for the biggest portion of the volunteered CPU time.

ttyl

You can try this link: http://www.finnfremforum.net/wcg_gallery/Sekerob%20charts/index.html