A popular “nonprofit organization” joke began in 1954:
 
“Sign on a Queens auto agency: ‘This is a non-profit organization. We didn’t plan it that way—that’s just the way it’s worked out so far.’”
 
The joke appeared on many business signs in the United States in the 1950s.
 
 
28 February 1954, Winona (MN) Daily News, “It Happened Last Night” by Earl Wilson, pg. 4, col. 3:
Sign on a Queens auto agency: “This is a non-profit organization. We didn’t plan it that way—that’s just the way it’s worked out so far.”
 
10 September 1956, Evening World-Herald (Omaha, NE), “Opinions” by Denman Koutze, Jr., pg. 11, col. 3:
Prominently displayed in a Council Bluffs tavern is this message: “This is a non-profit organization. We didn’t plan it that way, but it is…”
 
1 October 1956, Aberdeen (SD) American News, “It Happened Last Night” by Earl Wilson, pg. 4, col. 4:
DOWN IN ST. PETE, THE Houghton Co., which makes power motors, has the slogan, “When ya gotta mow, ya gotta mow” and adds: “This is a non-profit organization…we didn’t plan it that way, it just happened.”
   
Google Books
The Tax Digest
California Taxpayers’ Association
Volumes 34-35
1956
Pg. 306:
It reminds one of the sign seen hanging in a local restaurant which read : “This is a nonprofit organization, we didn’t plan it that way, it just happened.”
 
Google News Archive
22 February 1963, Pittsburgh (PA) Post-Gazette, “Pittsburghesque” by Charles F. Danver, pg. 25, col. 1:
Signs of the times (another one from the collection of Bob Massick, the Swissvale printer): “This Is a Non-Profit Organization. We Didn’t Plan It That Way, But It Is.”
 
Google Books
Learning a Trade:
A Craftsman’s Notebooks, 1955-1997
By Reynolds Price
Durham, NC: Duke University Press
2000
Pg. 122:
26 NOVEMBER 1958. Driving to Macon: in a Negro yard, bare and yard, one tom turkey alone, untied. And later, a single cow in a field.
—sign in a country store near Oxford, N.C.:
This is a nonprofit organization
We didn’t plan it that way
That’s just the way it’s work out.
 
Google Books
The Scooter Chronicles:
A Novel in Three Parts / Part Two
By Edward Beardsley
Bloomington, IN: iUniverse
2015
Pg. ?:
Someone said about a business: This is not a profitmaking organization. We didn’t plan it that way. It just happened.
   
Statesman Journal (Salem, OR)
Eradication by Mastication returns to laid-back roots
Henry Miller, Statesman Journal 9:03 p.m. PDT July 15, 2015
(...)
Everyone admittedly had a great time, he said, but the result was kind of like the punch line to an old joke: “This is a nonprofit organization. We didn’t plan it that way.”