This chart is misleading. It doesn't show which Amiibos are purchased the most by users, it shows how much stock was shipped to each region. Here is an article from IGN that contains a second chart that shows the sale-through rankings for each region.
http://www.ign.com/articles/2015/02/17/these-are-the-most-popular-amiibos-by-country
Basically, only 3 of the most-shipped Amiibos in NA are in the top 10 Amiibos desired by consumers (and each of those is at a lower rank than the amount of units shipped).
http://www.ign.com/articles/2015/02/17/these-are-the-most-popular-amiibos-by-country
Basically, only 3 of the most-shipped Amiibos in NA are in the top 10 Amiibos desired by consumers (and each of those is at a lower rank than the amount of units shipped).