Excel 2007 : Scatter Plot....Plotting one variable against another variable

Hello,

I am trying to create a scatterplot similar to the one attached (Scatterplotexample)

Instead of plotting arm strength against grip strength, I am plotting tree diameter (10-19, 20-29, 30-39, and 40-49) against tree age (30-80 years).

When I plot my data (as shown in My_data_scatterplot), The x-axis is tree age (which is what I want) but the y-axis is only plotting the number of trees that are that age.

I want to create a scatterplot has the y-axis representing diameter categories(10-19, 20-29, 30-39, and 40-49).

So that when you look at the chart you would see 4 separate scatter points at 30 years of age (x-axis) clustered at the 10-19 diameter mark (on y-axis).

Is this possible in excel 2007? I have tried arranging my data differently but have yet to get the chart I am seeking.

Thanks in advance for any help/advice!