“What do math teachers call retirement?”/“The ‘aftermath.’”

A joke about math teachers is:
 
Q: What do math teachers call retirement?
A: The aftermath.
 
The joke has been cited in print in 1968 and 1999.
 
     
Google Books
Faculty Conference; Papers and Proceedings
University of the Philippines
Manila: Bureau of Printing.
1968
Pg. 37:
This professor was just a few years away from retirement. He could not, as a professor of mathematics in another university did, repair to a haven of retirement and then call it “Aftermath.”
 
23 January 1999, Daily News-Record (Harrisonburg, VA),  “Bishop’s Mantle” by Jim Bishop, pg. 9, col. 5:
Do mathematics teachers call retirement the aftermath?
 
Google Groups: alt.sex.stories.d
{ASSD} Virtual Solstice Party—Six Months Late
Katie McN
7/4/00
(...)
Mathematics teachers call retirement ‘the aftermath’.
 
Google Groups: alt.humor.puns
Puns of the Weak 6/1/01
Stan Kegel
6/2/01
(...)
Mathematics teachers call retirement ‘the aftermath’ (Pun of the Day).
 
Google News Archive
9 March 2006, Leroy (MN) Independent, “Heartland News,” pg. 9, col. 4:
Mathematics teachers call retirement ‘the aftermath.’
 
Twitter
PuterPrsn™
‏@PuterPrsn
Aftermath: what math teachers call retirement. #pun
8:49 PM - 17 Apr 2009
 
Twitter
Hariharan Srikanth
‏@hari_srikanth
thinks that for math professors retirement is always the aftermath
3:27 PM - 23 May 2009
 
Twitter
Florencia Dufau
‏@Florrciita
@ddlovato “Math teachers call retirement the aftermath” xD hehe the best I can do! sorry!! hehe.. =)
9:41 PM - 26 May 2009
 
Twitter
Math Puns
‏@justsumpuns
What do math professors call retirement?
The ‘aftermath’
7:56 PM - 13 Mar 2016
 
Google Books
The Mammoth Book of One-Liners
By Geoff Tibballs
London: Constable & Robinson Ltd
2012
Pg. ?:
What do mathematics teachers call retirement?
The aftermath.
 
Google Books
Bad Science Jokes Jokes For Alkynes Of Scientists
By Melissa Miller
Lulu Publishing (Lulu.com)
2016
Pg. 26:
Math teachers call retirement “the aftermath”