More data thanks to HoneyRoastedPeanuts!
Stage performances by member in 2011:
01. Izuta Rina (Team KKS) - 179
02. Kojima Natsuki (Team KKS) - 170
03. Fujita Nana (Team KKS) - 169
04. Abe Maria (Team 4) - 167
05. Kobayashi Marina (Team KKS) - 165
06. Katou Rena (Team KKS) - 164
07. Kawaei Rina (Team KKS) - 157
08. Iriyama Anna (Team 4) - 155
09. Takeuchi Miyu (Team 4) - 147
10. Suzuki Shihori (Team B) - 142
11. Nakamata Shiori (Team 4) - 133
12. Morikawa Ayaka (Team KKS) - 124
13. Natori Wakana (Team KKS) - 115
14. Nagao Mariya (Team 4) - 110
15. Nakamura Mariko (Team 4) - 106
16. Ichikawa Miori (Team 4) - 105
17. Shimada Haruka (Team 4) - 103
18. Yamauchi Suzuran (Team 4) - 101
19. Suzuki Mariya (Team B) - 87
19. Chikano Rina (Team B) - 87
21. Ishida Haruka (Team B) - 81
22. Sato Natsuki (Team B) - 78
23. Tano Yuka (Team KKS) - 77
24. Shimazaki Haruka (Team 4) - 76
25. Kobayashi Kana (Team B) - 76
26. Iwata Karen (Team KKS) - 75
27. Miyazaki Miho (Team B) - 70
28. Saeed Yokota Erena (Team KKS) - 68
29. Sato Amina (Team B) - 65
29. Omori Miyu (Team KKS) - 65
and the members with the least amount:
66. Takajo Aki (Team A) - 24
66. Itano Tomomi (Team K) - 24
68. Kitahara Rie (Team B) - 23
69. Sashihara Rino (Team A) - 22
70. Takahashi Minami (Team A) - 21
70. Watanabe Mayu (Team B) - 21
72. Kashiwagi Yuki (Team B) - 19
73. Oshima Yuko (Team K) - 17
74. Kojima Haruna (Team A) - 9
75. Maeda Atsuko (Team A) - 9
76. Shinoda Mariko (Team A) - 7

Damn, and I thought Rena's 20 was low.
I guess in a way not performing at the theater means you (options are not exhaustive or mutually exclusive):
1. are popular
2. are ready to move on to do other things (dorama, movie, variety, fashion, gravure, etc)
On the other hand, if we look at the number of performances by team:
Team B - 100
Team KKS - 94
Team K - 66,
Team A - 43
Team 4 - 35
Team B and the KKS have performed a lot more than the other teams. This could indicate that MaYuki could be among Acchan levels percentage wise. It also explains why some of these girls have done a lot more performances than others.
Props to all the kks and subs (and regulars) who are working hard at the theater
