It's pretty cool, google "google trends" and you can find out the relative frequency of search terms. Each search term is unique, so "wii" and "wii u" are sperate. Wii U didn't exist in '06 and a lot of people searching wii u now will just search wii, so you should enter both as seperate searches and combine the totals to see total searches on wii products. You can see the peaks and valleys over the years, with the highest intersts during Christmas of peak years '06-'09. Further to this, an investment research firm found stats to directly link google searches with eventual purchases. Their research found overal searches down from wii levels but up in Japan. This was well in advance of peak search season however, so I've continued to follow the trends.
