“Why do people work as bakers?”/“Because they knead the dough.”

An old joke plays upon the words “knead” and “need” and the slang sense of the word “dough” (money):
 
Q: Why do people work as bakers?
A: Because they knead the dough!
 
The “knead the dough” food joke has been cited in print since at least 1898.
 
       
23 May 1898, Middletown (NY) Daily Argus, pg. 7, col. 2:
Sounds Impudent.
Mrs. Youngwife can’t get through her head
The ways of her servants: for-lo!
What she says to the cook: “We need bread.”
The cook says: ‘Then I’ll knead the dough.”
—Harlem Life.
 
Google Books
November 1905, Typographical Journal, pg. 536, col. 2:
All should help the bakers, because they “knead the dough.”
 
Google News Archive
19 January 1915, Spokane (WA) Spokesman-Review, pg. 4, col. 5:
The price of wheat makes flour go up,
The way things often go;
The bakers boost the price of bread
Because they knead the dough.
 
18 March 1918, Charlotte (NC) Observer, “Trench and Camp,” pg. 5:
Sergeant Cleveland says they call them doughboys, because they knead the dough.
 
6 April 1924, Los Angeles (CA) Times, pg. B15:
Some one has already pulled that crack about the actors who joined the cast of Bread because they need the dough.
 
15 November 1925, Chicago (IL) Daily Tribune, “Slanguage,” pg. G2:
She thinks all bakers are hard up because they knead the dough.
 
Google Books
Biggest Riddle Book in the World, Part 2
By Joseph Rosenbloom
New York, NY: Sterling Publishing Company
1976
Pg. 25:
Why do people work as bakers?
Because they knead (need) the dough.
 
Google Books
777 Great Clean Jokes:
A Sparkling Collection of Unsullied Humor
By Jennifer Hahn
Uhrichsville, OH: Barbour Pub.
2006
Joke 186:
Why do bakers work so hard?
Because they need the dough.