Oricon Half Year Ranking 2013 report published.http://www.oricon.co.jp/music/special/2013/musicrank0621/index.html
Earning rankings (single + album + music DVD + music BD):
#1 - Arashi (10.95 billion yen, 3.022mil sales) - 2 DVDs, 2 singles
#2 - AKB48 (6.86 billion yen, 3.582mil sales)
#3 - Momoiro Clover Z (3.92 billion yen, 868k sales)
#4 - Kis-My-Ft2 (2.61 billion yen, 1.129mil sales)
#5 - Kanjani∞ (2.55 billion yen, 665k sales)http://www.oricon.co.jp/news/rankmusic/2025847/full/
With 0 singles released (though lots of previous years singles still sold quite a bit and charted) and mainly rely on albums / DVD / BD, Momoiro Clover Z has the best earning : sales ratio.