years of service
(3) The “years of service” of an individual who was an employee on August 29, 1935 , shall, if the total number of his “years of service” as determined under subdivisions (1) and (2) is less than thirty, also include his service prior to January 1, 1937 , but not so as to make his total years of service exceed thirty: Provided, however, That with respect to any such individual who rendered service to any employer subsequent to December 31, 1936 , and who on August 29, 1935 , was not an employee of an employer conducting the principal part of its business in the United States, no greater proportion of his service rendered prior to January 1, 1937 , shall be included in his “years of service” than the proportion which his total compensation (without regard to any limitation on the amount of compensation otherwise provided in this subchapter) for service subsequent to December 31, 1936 , rendered anywhere to an employer conducting the principal part of its business in the United States or rendered in the United States to any other employer bears to his total compensation (without regard to any limitation on the amount of compensation otherwise provided in this subchapter) for service rendered anywhere to an employer subsequent to December 31, 1936 . Where the “years of service” include only part of the service prior to January 1, 1937 , the part included shall be taken in reverse order beginning with the last calendar month of such service.