By the end of December, 2 million Windows Phone 7 devices had shipped to retailers, Microsoft told Bloomberg News on Wednesday.

But that still doesn’t tell us how many Windows Phones have been sold to consumers. And it suggests Windows Phone sales are far below Microsoft’s expectations.

A month ago, Microsoft said 1.5 million Windows Phones had shipped in the first six weeks — from the Oct. 21 Europe-Asia launch until around Dec. 2. That means from then until the end of December, just about 500,000 more Windows Phones were shipped.

500,000.

By contrast, a Google executive said in December it was activating 300,000 Android phones per day.

Granted, Android — now the best-selling smart-phone platform — has much more momentum than Windows Phone 7. And it took Android a couple of years to get there.

It’s apparent that the Windows Phone shipment rate also slowed. About 1.5 million devices were shipped in six weeks, for an average of 250,000 per week; then 500,000 were shipped in the next four weeks, or about 125,000 per week. And that was during the holiday shopping rush.

It’s clear: Microsoft has a huge mountain to climb.

Microsoft today also said there now are more than 6,500 apps in the Windows Phone marketplace. (An unofficial tally can always be seen in the column immediately to the right.) And customer satisfaction is at 93 percent, Microsoft said, with brand awareness of 66 percent.

Al Hilwa, a Seattle-based analyst with research firm IDC, thinks Microsoft is making good progress. At this stage in the process, facing formidable foes in Google and Apple, Microsoft must keep pushing, he said.

“There is no question that this is a platform in the process of being birthed,” Hilwa told seattlepi.com in an e-mail. “The issue is what can we tell about the future from these numbers.

“To me, it says that if they keep pushing as hard as they have, bring new phones out, improve the software, cover more carriers and countries, add developers and apps, they really have a good chance to have some serious market share in a couple of years. I think at this point we can say that early childhood is moving as expected and they are making headway.

“If you are Apple and Google you need to be looking in the rear-view mirror more anxiously now because the competition is definitely starting to heat. If you are anyone else, you are probably more worried as the market changed substantially compared to a few months ago.”