My top 20 activity log: (note, this doesn't take into account the games I played on my previous 3ds!)

Pokemon x - 352 hours

Pokemon omega ruby - 337 hours

Fantasy life 151 hours

Pokemon sun - 80 hours

a link between worlds - 48 hours

animal crossing new leaf - 48 hours

Monster hunter 4 - 36 hours

Triforce heroes - 34 hours

Ocarina of time - 30 hours

pokemon Y - 30 hours

Pokemon bank - 27 hours

Mario kart 7 - 24 hours

Luigi's mansion - 23 hours

Majora's mask - 20 hours

Pokemon moon - 20 hours

Nintendo e shop - 19 hours

residen evil revelations - 14 hours

Kid icarus - 12 hours

steamworld dig - 11 hours