Excel 2000

I have a large database which produces 18 charts with 4 measurements for 4+
years - Data, Target, Stretch, Threshold. Instead of changing each of 72
Source Data cells each month to include the new month, I am thinking of
creating named ranges for the 72 columns, and include rows that will take the
data to 2010.

Questions:

1) Will Excel accept 72 named ranges, or is there a maximum?

2) Is there an easier way to enter in the named ranges other than one at a
time? (Insert, Name, Define).

3) How to handle the x-axis to not include the future months/years in the
charts? Will I have to redefine Column A (date) in each of the 18 chart's
Catagegory Axis Label in the Source Data Series box each month?

TIA
CaroleO