I currently have a line chart that I've created in Google charts and have a question that I can't seem to find in the docs. Attached is a picture of what I need, but in text:

I need to be able to annotate specific values along the x-axis with a vertical line, but instead of having the text labels rotated to be perpendicular to the x-axis (see: How can I add a vertical line on the X axis in a Google Chart' chart (Line type)?), I need the text to be above the vertical line at the top of the graph, parallel to the x-axis.

Here is a drawn image of what I'm looking for:

I was thinking maybe doing this with annotations, but open to any ideas.