We are thinking about turning on the header search bar and would like to see if it actually increases the number of searches that users do. But the only search stat I can find is /admin/reports/trending_search which is obviously not the right thing.
What am I missing?
I think you’ll need a custom data explorer query. Do you have that plugin installed?
Oh… Yes I do have it installed. I need to read the docs on that. Thank you.
If I want help, am I in the right category to get it? This seems like it would be something common for people to need. But I guess everyone thinks this about their own needs, lol.
If you’re looking for help with reports on your data then this is the right category. 
It’s tricky to pre-empt what reports will be useful to lots of people. But the data explorer is great for creating anything that may not already exist. There may even be a few existing ones you can use for inspiration if you have a search of the sql-query and search tags.
Depending on how much help you need, people can often suggest queries or help you refine one you’ve come up with here as well.