“98” or “Ninety-eight” (assistant manager)

 
Newspapers.com
9 February 1930, Tampa (FL) Sunday Tribune, “Soda Jerkers Here Talk in Language Hard to Understand,” pt. 4, pg. 6, col. 2:
98—Here comes the assistant manager.
 
Newspapers.com
29 March 1936, Helena (MT) Daily Independent, “National Youth Administration Compiles Lexicon of the Soda Jerker After Five Months Work” by Helen Dallas, pg. 2, col. 8:
“Ninety-eight” is the manager, “ninety-nine” is the head soda man, and a “pop boy” is a soda man who does not know his business.
 
Newspapers.com
27 September 1981, The Herald Statesman (Yonkers, NY), “Counterwailing” by Dan Carlinsky, Suburdia Today, pg. 18, col. 4:
98. The assistant manager.
 
Newspapers.com
10 July 1985, The Times-Mail (Bedford, IN), “Soda jerk unique on American scene” by Ink Mendelsohn, pg. 5, col. 5:
NINETY-EIGHT—the manager
 
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29 November 1997, Pueblo (CO) Chieftain, “Word Mysteries” by Chris Woodka, pg. 5A, col. 4:
99—The boss. The assistant manager was 98.