According to Oricon, seiyu Mizuki Nana's new album CD "ULTIMATE DIAMOND" was sold 74,000 copies and ranked the first in the weekly CD sales ranking for June 1st - 7th. It's for the first time in 41 year history of Oricon ranking that a seiyu wins the top in the sales ranking.

Her single CDs "ETERNAL BLAZE" and "SECRET AMBITION" ranked the second in 2005 and 2007 respectively, but she had never won the top.
Mizuki Nana said "Words fail me to see such a daydream like event. I wanna convey my gratitude to all the people who support me. Thank you very much."

Source: NTV

Records of Oricon CD Ranks (Anime & seiyu CDs)
1st
"ULTIMATE DIAMOND" Mizuki Nana (2009)

2nd
"BPM 150MAX" TWO-MIX (1996)
"ETERNAL BLAZE" Mizuki Nana (2005)
"SECRET AMBITION" Mizuki Nana (2007)
"Motteke! Sailor Fuku" Lucky Star OP (2007)
"Climax Jump DEN-LINER form" Kamen Rider DEN-O OP (2007)

3rd
"bertemu" Hayashibara Megumi (1996)
"TRUTH〜A Great Detective of Love〜" TWO-MIX (1998)
"Northern lights" Hayashibara Megumi (2002)
"Happy☆Material" Mahou Sensei Negima! OP (2005)
"Motteke! Sailor Fuku Re-Mix001〜7 burning Remixers〜" Lucky Star (2007)
"Triangler" Sakamoto Maaya (2008)

Source: Music Room