We all know that Microsoft chief executive Steve Ballmer loves developers. If you’ve somehow missed his infamous video clip over the past few years, go here and pick your poison.

There’s just one problem with this love. Since the launch of Windows Vista, apparently it’s unrequited.

Only 8 percent of developers are writing applications for Vista this year, according to a report from Evans Data. Again, not eighty percent — eight.

By 2009 that number is expected to triple to a still abysmal 24 percent. That’s a major problem. Why? Because shortly thereafter, Windows 7, the codename for the next iteration of Microsoft’s operating system is expected to launch.

If these numbers have any merit, that means that Vista throughout its lifespan will basically be a non-starter. It’s going to be hard to sell an operating system if no one is writing applications for it.

Despite Ballmer’s claims that Vista is selling “incredibly well,” it’s hard to find anyone outside of Microsoft would doesn’t consider the operating system to be a major disappointment. In fact, Vista is becoming such a problem that some are now expecting its slow adoption rate to shave some $395 million off of Microsoft’s revenues in the 2009 fiscal year.

This follows a report from a few months ago suggesting that the Windows operating system was on the verge of collapsing.

Granted, the 8 percent data is taken from only 380 North American developers surveyed, but over half of them said they were still developing for previous iterations of Windows. Meanwhile, Apple’s OS X has seen a 380 percent surge in growth as a targeted development platform.

It might be time for an encore of “Developers, developers, developers, developers.”