Anime Programming in the US
Making a Living in Manga in Japan with Felipe Smith
Lost in Translation
The 68th volume also received a four million print run when it shipped in Japan in November. The 67th volume set a manga record for the most copies in its first printing with 4.05 million copies. The previous two volumes matched but did not beat the former record of 4 million copies set by volume 64 in 2011.
Over 280 million copies of the entire manga series have been printed; One Piece has had the highest number of copies printed of any Shueisha manga series in Japan.
Source: Mainichi Shimbun's Mantan Web