retirement age
(1) The term “retirement age” means— (A) with respect to an individual who attains early retirement age (as defined in paragraph (2)) before January 1, 2000 , 65 years of age; (B) with respect to an individual who attains early retirement age after December 31, 1999 , and before January 1, 2005 , 65 years of age plus the number of months in the age increase factor (as determined under paragraph (3)) for the calendar year in which such individual attains early retirement age; (C) with respect to an individual who attains early retirement age after December 31, 2004 , and before January 1, 2017 , 66 years of age; (D) with respect to an individual who attains early retirement age after December 31, 2016 , and before January 1, 2022 , 66 years of age plus the number of months in the age increase factor (as determined under paragraph (3)) for the calendar year in which such individual attains early retirement age; and (E) with respect to an individual who attains early retirement age after December 31, 2021 , 67 years of age.