Beder3004,
In addition to Sekerob's collection of graphs you can also use the Research section of WCG's website. For most active projects the first paragraph Project Overview contains a link to the status report(s) of that project, seen from the lab's perspective.
Note that some projects are "open", i.e. the work to do and the number of WUs to process is not fixed from the beginning, therefore the concept of "percentage of work done" is a little vague. Some others have a very specific work to do and for those a percentage is more meaningful, although there is always a delay between the work we do and the work the labs have in their hands.

Surprisingly the project with the most detailed and up-to-date information, HCMD2, is the only one which has no link to this info in its Project Overview. I hope that WCG's admins will correct this situation on a future website update.
This is the link to HCMD2's Status Page
In addition to the weekly percentages don't miss their link to their batch status page which shows a graphical representation of the results they have received and of what has still to be done.

Cheers. Jean.