The Wii U
While the NPD no longer provides specific sales numbers for hardware, a representative does tell us that sales of the Wii U hardware for its first three months on the market are down 38 percent from what the Wii's numbers were at that same point. We're told by someone with access to the NPD's data that sales for January were "well under" 100,000 units.
Similarly, we don't know any software sales numbers, but from NPD's report we can see where Wii U SKUs of multiplatform games compare to other SKUs, and it doesn't look good.
In instances where a game exists on both the Wii and the Wii U (Just Dance 4, NBA 2K13, Madden NFL 13, Skylanders Giants and FIFA Soccer 13), the Wii version came out on top every time. In Madden's case, it was even outsold by the portable version for Sony's ailing Vita handheld.