TOP 10 revenue makers of 2007 according to Oricon (Note: Oricon doesn't include downloads):
2007 Artist Total Sales Ranking aka Highest Revenue Makers
01 Koda Kumi - 7.3544 billion yen
02 Hamasaki Ayumi - 7.0576 billion
03 Mr. Children 6.9182 billion
04 EXILE - 5.4111 billion
05 KAT-TUN - 5.247 billion
06 Otsuka Ai - 5.2159 billion
07 Kobukuro - 4.3669 billion
08 KinKi Kids - 4.3143 billion
09 Arashi - 3.828 billion
10 L'arc~en~Ciel - 3.4376 billion
http://www.oricon.co.jp/music/special/071218_01_03.html
Highest Revenue Makers since 2000
2000 - Hamasaki Ayumi
2001 - Hamasaki Ayumi
2002 - Utada Hikaru
2003 - Hamasaki Ayumi
2004 - Utada Hikaru
2005 - ORANGE RANGE
2006 - Koda Kumi
2007 - Koda Kumi
http://www.oricon.co.jp/news/rankmusic/40468/
2005 ranking for Ayu: Overall #4 (Females #2) with 6.9083 billion yen
2006 ranking for Ayu: Overall #5 (Females #2) with 6.8927 billion yen