what are the biggest sororities nationally?
['Chi Omega: 300,000 members.', 'Kappa Alpha Theta: 250,000 members.', 'Delta Delta Delta: 238,000 members.', 'Kappa Kappa Gamma: 235,000 members.', 'Pi Beta Phi : 230,000 members.', '(tie) Kappa Delta: 230,000 members.', 'Delta Zeta: 220,000 members.', 'Alpha Delta Pi: 215,000 members.']