This newly completed table turned up Sunday on a Japanese blog.
It lists women seiyuus by years in the business, giving their ages as well, and with a little pic of each one. I have transliterated the Japanese names and adapted the title and notes.
The newest seiyuus are Oogame Asuka and Kanemoto Hisako, who started in 2009, making this their second year as seiyuus. The most experienced are Hayashibara Megumi (25th year) and Minaguchi Yuuko (26th year). Click here or on the image to go to the full-sized table:
Not all ages are perfectly accurate: Yuuki Aoi is said to be 19, but will not turn 19 until March 2011.