Smallest percentage of charters active?

[Tulip86]

Just stating in advance that I don't have the full numbers for all NPC sororities. Numbers are from (inter)national websites if possible. Otherwise from Irishpipes' thread A lot of NPC sororities don't openly name inactive chapters, so information may not be up to date or severely incorrect. Please post correct information if this list isn't accurate, and I'll update.

Active/total chartered (closed) as of sept. 3 2013

Alpha Chi Omega: 137/184 (47) 25.54%
Alpha Delta Pi: 146/209 (63) 30.14%
Alpha Epsilon Phi: 53/153 (100) 65.36%
Alpha Gamma Delta: 126/195 (69) 35.38%
Alpha Omicron Pi: 124/199 (75) 37.69%
Alpha Phi: 157/208 (51) 24.52%
Alpha Sigma Alpha: 105/150 (45) 30%
Alpha Sigma Tau: 96/133 (37) 27.82%
Alpha Xi Delta: 121/212 (91) 42.92%
Chi Omega: 179/ 230 (51) 22.17%
Delta Delta Delta: 138/189 (51) 26.98%
Delta Gamma: 146/190 (44) 23.16%
Delta Phi Epsilon: 89/164 (75) 45.73%
Delta Zeta: 158/ 297 (139) 46.8%
Gamma Phi Beta: 129/176 (47) 26.7%
Kappa Alpha Theta: 133/174 (41) 23.56%
Kappa Delta: 149/ 222 (73) 32.88%
Kappa Kappa Gamma: 140/162 (22) 13.58%
Phi Mu: 117/ 211 (94) 44.55%
Phi Sigma Sigma: 108/182 (74) 40.66%
Pi Beta Phi: 134/188 (54) 28.72%
Sigma Delta Tau: 62 /103 (41) 39.8%
Sigma Kappa: 115/211 (96) 45.5%
Sigma Sigma Sigma: 112/189 (77) 40.74%
Theta Phi Alpha: 53/98 (45) 45.92%
Zeta Tau Alpha: 162/215 (53) 24.65%