AP
It's unlikely Microsoft will ever announce specific numbers with the Surface. It appears to be following the Amazon route of not saying anything useful.
There was no mention in Microsoft's earnings release about Surface sales. We spoke with Microsoft's IR manager Bill Koefoed about the earnings. He wouldn't give us any details on Surface sales.
He just said, "We think of as part of the overall Windows story," and so they're not going to break out unit sales.
We are just speculating here, but we bet that if Surface sales were great it would put out numbers. When the Kinect for Xbox was released Microsoft proudly told the world it sold 1 million units in 10 days.
We wouldn't be shocked to randomly hear some numbers like when Google occasionally releases Android activations or the run rate of its display ad business. But, we're not expecting routine updates on the state of the Surface.