Why does the graph's time axis not match the dates in the selected data?

I follow what you did, but the graph you've created omits the ordered pairs at 12/31/2019.

Background: I'm creating a spreadsheet to track % member retention and % new members for the chapter of a larger group. The ordered pairs are generated from a download of a group's membership database and a VBA program that extracts % member retention and % new members for a single date. Successive downloads will generate a plot showing how the chapter's % retention and % new changes over time. The data range includes enough cells to plot the % retention and % membership a couple of times per month, for a year, and have a couple left over. However, some chapters will only create this plot a couple of times per year.
Extending the horizontal lines to 12-31-2019 is important to show end-of-year membership goals.

I need to keep the horizontal axis representing dates (as it did in the first graph), instead of 'flipping' to counting the number of dates (as it did in the second graph), and I need the horizontal lines to extend through 12-31-2019. Any ideas on how to force this with the data?

The file in the original post has the axis range C29:AD29, so it includes the ordered pairs from 12-31-2019. protonLeah shortened the range in order to force the graph's horizontal axis to represent dates (as it did in the first graph), instead of 'flipping' to counting the number of dates (as it did in the second graph). What I need is the axis range C29:AD29 and graph's horizontal axis to represent dates.

When I open the graph in the original post and select the data, I see the following (which includes C29:AD29):
Capture.JPG
Do you see something different?

Since I don't even know what 'category labels' are, you are probably honing in on my problem. What would you suggest to resolve this?

When I follow your directions and click on the Edit button, I see the following:

Capture.JPG
;i.e., the range C29:AD29 is already selected. Therefore, selecting the range C29:AD29 will not fix my problem with the graph's horizontal axis 'flipping' to counting the number of dates (as it did in the second graph), instead of represent dates (as it did in the first graph).

It looks just like the graph I said I wanted in the first post. What did you do to 'get there'?

I can 'get there' by creating the graph all over again, but the graph occasionally 'flips back' to counting the ordered pairs instead of placing the ordered pairs on a number line representing dates. Since I'm creating this spreadsheet for other chapters, I don't want them to periodically have to recreate graphs, so I hope you did something other than recreate the graph and something that I can replicate to freeze the graph's horizontal axis for other chapters.

OK. Thanks. Then I'll just have warn the chapters that the graph breaks ocassionally and instruct them on now to recreate the graph.