What is the largest national sorority?

[Angels&Arrows]

Okay... Because I had some down time today and research is my thing...

This is from each individual GLOs national website! If the information is incorrect... Please let me and your Nationals know... because I pulled it off the GLOs website, with the exception of Alpha Epsilon Phi and Theta Phi Alpha (they do not have active websites). The list is only consist of the Members of the National Panhellenic Council. If you have any additional information, please let me know... I will add it. Same goes for changes.

-----------------------------Year-------Current--Chapters
-----------------------------in NPC-----Active----Closed--% Closed
Alpha Omicron Pi---------1905------176
Chi Omega----------------1903------164
Delta Zeta ----------------1910------161
Alpha Phi------------------1902------148
Zeta Tau Alpha-----------1909------143--------76-------35%
Delta Gamma-------------1902------142
Pi Beta Phi----------------1902------134--------25-------16%
Alpha Delta Pi------------1909------133
Delta Delta Delta--------1902------133--------39-------23%
Alpha Chi Omega--------1903------133
Kappa Kappa Gamma---1902------129
Phi Mu----------------------1911------123
Kappa Alpha Theta------1902------122--------39-------24%
Kappa Delta---------------1912------122
Gamma Phi Beta----------1902------114
Alpha Gamma Delta------1909------115--------66-------36%
Alpha Sigma Tau----------1951------113--------37-------25%
Phi Sigma Sigma----------1951------113--------57-------34%
Alpha Xi Delta-------------1904------112
Sigma Kappa--------------1905------109
Sigma Sigma Sigma-------1951------107
Delta Phi Epsilon----------1951-------78-----------4-------5%
Alpha Sigma Alpha--------1951-------73
Sigma Delta Tau-----------1951------ 57---------38-------40%
Alpha Epsilon Phi----------1951------N/A
Theta Phi Alpha------------1951------N/A