1 - 150.80 浜崎あゆみ Ｄａｙｓ／ＧＲＥＥＮ
it seems that Ayu has no competition and that a #1 is 99% hers.
source:
http://www.oricon.co.jp/rank/ns/
2 - 32.00 田村ゆかり Ｔｏｍｏｒｒｏｗ
3 - 25.10 ＢＵＣＫ－ＴＩＣＫ ＨＥＡＶＥＮ
4 - 24.50 ＭＩＳＩＡ ＣＡＴＣＨ ＴＨＥ ＲＡＩＮＢＯＷ
5 - 18.00 ｒａｖｅｘ Ｉ ＲＡＶＥ Ｕ ｆｅａｔ．ＤＪ ＯＺＭＡ
MW's NINKI:
Ayumi Hamasaki - Mirrorcle World 84.80