Here is my predicament:

I have a table containing the fields ProjectID, StartDate, and EndDate. I would like to be able to calculate the percentage of the Project's lifespan taking place in each year.

For example, this is what I am looking for:

1999 2000 2001 2002 2003
Project 1
01/01/1999 - 31/12/2003 20% 20% 20% 20% 20%

Project 2
01/01/2001 - 31/12/2003 33% 33% 33%

And so on...

I have been trying to create a cross-tab query to do this, but I can't figure it out.
I suspect the solution may be complex, but if anyone can help it would greatly appreciated.