I'm going to compare Wii U's 2013 sales to 2014. I'm counting Week Ending January 4th, 2014 as 2014, since most of the week is in 2014, and I'm starting from Week Ending January 5th, 2013 for 2013. The comparison is below.
2013 - 278,539
2014 - 318,509
2014 is obviously winning, and it pretty much guaranteed that it will stay ahead.