How Many Programmers are there?

I just saw this interesting blog post, here, that states that there are over 9 million Java programmers. That number doesn’t ring true with me, my last recollection -- from who knows where -- was that there was roughly a million or so programmers in all languages/technologies.

For this type of number, I’d like it to be restricted to people that are making a “living” off of programming, doing it on a full-time or nearly full-time basis. The number of hobbyists and students is interesting, but these numbers fluctuate widely with popularity. There are also a lot of 'coders' in operations and support roles, but they tend to write small works that smooth over bumps or glue together existing pieces. It's the number of people doing the heavy lifting that I am curious about.

No doubt it is a difficult number to find. You can’t just measure downloads, or up and coming job ads. And there is a huge segment of older programmers out there making a good living from the mature technologies like COBOL and mainframes, but most of them have a near-zero web presence. Still, they are an important group because their technologies run a good majority of the mission critical applications and they often have more refined engineering skills and processes.

If anyone has any links, or comments, I’d be really interested. I’ve seen a lot of resources, but I’ve never found one that I felt really captured this number correctly.