Excel 2002

I have a simple chart: two columns (A and B) and 29 rows.
Column A is years, from 1980 to 2008.
Column B is some value between 0 and 9.

Example:
1980 0
1981 1
....
2008 4


I created a chart.
It plots the points fine, they are where they should be.
The Y axis is fine, numbers from 0-9, label is OK.

But I cannot get it the X axis to use the years (1980 - 2008).
Instead it is labeled 1-29, which are the Excel _row numbers_.

I want the x axis values to be the _years_ from Column A.

How do I do this?
Thanks.