Bernie,

Thank you for the help. Your method solved the problem that time, but
now it's not working now with the following set of data:

-1 0.07
0 0.07
2 0.09
4 0.14
6 0.10
9 0.08
10 0.09

I can create a perfect chart using rows the first 6 rows above, but as
soon as I add the last row of data, it wants to plot everything
sequentially as "1" through "7". I don't understand why this would
change just because of the "10".