The interactive graph is here. (The picture below is just a snapshot, and *not* the interactive graph.)
The Tableau gives the impression that more countries held US Treasuries now than 5 or 10 years ago. However, the data source the blog post referenced doesn’t go back to March 2000. So, it isn’t clear to me whether that is indeed the case, or if there are some issues with the data not being broken out from the “all other” categories for some countries in some years.