AC is the biggest series in Japan right now with 5m sales average, with the added momentum of NS and the situation of combined home and portable userbases it has a good chance of catching and overtaking Pokemon G/S' total sales of 7.2m LT which would make it the second best selling game in the region first is Pokemon R/B/G at 10.2m which would be quite a target to beat but right now only AC has any kind of shot at hitting it.