Denys has already done an excellent job of answering your real question (with
the on small exception of noting that CD-R are supposed to last much longer in
a dark place than in sunlight.  The 100-year figure I had heard was for the
gold-colored CD-Rs, so look carefully before you buy.  There are definite
differences.

As you've already gotten the answer you needed, I thought I'd respond to this:

> We are now down to about 15 and are betting on who goes next.

Which reminded me of a poem by W.S. Gilbert (of Gilbert & Sullivan fame) called
"the Yarn of the 'Nancy Bell'".  If you don't know it already, you can find it
numerous places.  One which appears to be correct is:

  http://www.hutchison.org/poetry/gilbert_w_s/bell.html

Ted
--
Ted Ashton ([log in to unmask]), Info Sys, Southern Adventist University
          ==========================================================
Mathematical discoveries, small or great are never born of spontaneous
generation.  They always presuppose a soil seeded with preliminary knowledge
and well prepared by labour, both conscious and subconscious.
                        -- Poincare, Jules Henri (1854-1912)
          ==========================================================
         Deep thoughts to be found at http://www.southern.edu/~ashted