A better measure is how much they spent on Microsoft stock through the program, since employees elect to put a certain percentage of their paycheck toward the program; they don't designate a specific number of shares they'd like to buy. Their spending, too, has declined.

Microsoft employee spending on the ESPP during the past three years was as follows:

2007: $5,857.41 per employee
2006: $5,906.37 per employee
2005: $6,425.96 per employee

I calculated this by dividing the total employee contribution for each year, as reported in this SEC filing, and dividing it by the number of employees Microsoft reported on June 30 of each year (listed here). Further scrutiny is welcome.

As you can see, the trend is in the same direction I identified in the earlier post. While the decline from 2006 to 2007 is not that big, what about the drop from 2005 to 2006?

As several readers noted, it's hard to imagine why an employee who can afford to wouldn't participate in the program. Even the most bearish employee can get an immediate 10 percent gain each quarter by selling their shares the day after they acquire them at 90 percent of market price through the program.

One suggestion is the average Microsoft salary could be decreasing as the number of international hires increases. That's speculation and I don't have data on U.S. vs. ex-U.S. Microsoft salaries. But we do know that Microsoft has been adding employees outside the U.S. at a faster rate (14.5 percent for the 12-months ended last July 2007) than its employment growth overall (10.6 percent for the same period).

Also, I think it's fair to assume that regardless of regional salary differences, the types of jobs Microsoft is adding overseas are skewing toward lower-paying sales and marketing functions rather than the core product development work, much of which is still done in Redmond (though even those functions are performed globally). Recall that more than 60 percent of Microsoft's sales now come from international markets, executives said at the company's most-recent quarterly earnings report.