I have tried to reproduce the problem you mentioned.

My guess is that, **Excel has interpreted the YEAR column (say column A) as part of the data**, because Excel will try to interprete any number-like value as number.

Here is a **simple trick** that solve the problem.

- Change the value in YEAR column (ie. 1999, 2000, 2001, ...) to any text (ie. A, B, C, ...)
- Highlight both columns (eg. A1:B10), and press the chart button as usual.

(As Excel cannot convert A/B/C to any number, it will make the A/B/C as axis label correctly.)
- Change the text back to the YEAR (1999, 2000, ...)

Alternatively, **if you cannot change any cell value**, you can manually set it in the chart wizard.

- Highlight ONLY the REVENUE column (eg. B1:B10), and press the chart button.
- Set A2:A10 as axis label in the wizard, and continue with the chart wizard

(As I only have Excel 2003 at the moment, I will update the answer if there is any difference in Excel 2007.)