Kresnik on 13 January 2015
http://gematsu.com/2015/01/sword-art-online-lost-song-developed-artdink
Sword Art Online: Hollow Fragment has sold 450k worldwide, including 70k in the USA.
Digital-only USA release.
Also, 90k in Asia, of which I'm sure a decent amount is physical and untracked by VGC.