For those who are interested in attendance stat, here is the list of the most frequent performers on AKB theater stages during January, 2012 through August, 2012.
#1 Morikawa Ayaka (11th gen) --- 112 times
#2 Omori Miyuu (12th gen) --- 111 times
#3 Fujita Nana (10th gen) --- 97 times
#4 Izuta Rina (10th gen) --- 89 times
#5 Tano Yuuka (12th gen) --- 88 times
#6 Mutou Tomu (12th gen) --- 81 times
#7 Natori Wakana (11th gen) --- 79 times
#8 Kobayashi Marina (10th gen) --- 76 times
#9 Sasaki Yukari (12th gen) --- 75 times
#10 Saeed-Yokota Erena (12th gen) --- 74 times
#11 Suzuki Mariya (7th gen) --- 69 times
#12 Kobayashi Kana (2nd gen) --- 67 times
#13 Sato Natsuki (2nd gen) --- 65 times
#13 Oshima Ryoka (13th gen) --- 65 times
#15 Suzuki Shihori (7th & 11th gen) --- 64 times
#15 Chikano Rina (5th gen) --- 64 times
Source:
http://d.hatena.ne.jp/tomakomai01951/20120905/1346809961