Let me ask you a question, Lee (or anyone else who knows the answer), just to satisfy my own curiosity.
Perhaps it was because you threw me off when you said "this ought to keep you busy," implying that obtaining the correct answer should take some time, which it obviously didn't. But instead of doing the intelligent thing and referencing the Statistics section at the bottom of the Forums page as you mentioned, I went to that page and manually added all of the threads and posts according to the totals provided in those respective columns.
I wound up with 147,978 threads and 2,046,183 posts, which is how I came up with my guess of 13.8.
48 hours later, I see that the statistics show 158,513 threads and 2,289,675 posts. Obviously there haven't been 10,000+ new threads and 240,000+ new posts in the last 2 days. So what accounts for the difference?