“What’s the difference between boogers and broccoli?”/“Kids won’t eat broccoli.”

Children hate certain foods. A popular joke is:
 
Q: What’s the difference between boogers and broccoli?
A: Kids won’t eat broccoli.
 
“What’s the difference between Brussels sprouts and boogers? Kids won’t eat Brussels sprouts” was cited in print in 1988. “What’s the difference between boogers and broccoli?” was cited in 1989.
 
     
Google Books
January-February 1988, Spy magazine, pg. 93, col. 2:
Well, here’s a joke I heard a teacher tell: “What’s the difference between Brussels sprouts and boogers? Kids won’t eat Brussels sprouts.”
   
Google Books
The Critic
Volume 44
1989
Pg. 100:
“What’s the difference between boogers and broccoli?”
“Little boys won’t eat broccoli.
 
3 October 1989, The Orange County Register (Santa Ana, CA), “Candy maker thumbs its nose at good taste” by Judy Markey, pg. E2, col. 1:
And I didn’t launch a public-relations campaign for it (Boogers candy—ed.) featuring a tall green character called Boogerman telling “boogerjokes,” i.e., “What’s the difference between boogers and broccoli? Kids don’t eat broccoli.”
     
Google News Archive
22 December 1991, The Ledger (Lakeland, FL),“Judging,”  pg. 3C, col. 1:
Speed warmed up the room with a story told by one of her students.
 
“What’s the difference between broccoli and boogers?” she asked.
 
“Kids don’t eat broccoli,” she answered to the delight of the crowd.
 
Google News Archive
11 December 1993, Milwaukee (WI) Senintel, “Wolfberg is falling-down hilarious” by Dave Tianen, pg. 16B, col. 4:
Or jokes he steals from his 7-year-old son:“What’s the difference between boogers and broccoli?...Kids won’t eat broccoli.”
     
Google Books
Eyeballs for Midnight Snack
By M. M. Ragz
New York, NY: Pocket Books
1994
Pg. 87:
“What’s the difference between boogers and broccoli?” Iggy asked.
 
“I don’t know, what?” Peter asked.
 
Iggy was already laughing as he said, “Little kids don’t eat broccoli!”
 
Google Books
Hocus-Jokus:
How to Do Funny Magic
By Steve Charney
Minnetonka, MN: Meadowbrook Press; New York, NY: Distributed by Simon & Schuster
2003
Pg. 23:
“Can anyone tell me the difference between Brussels sprouts and boogers? I’ll tell you: Kids won’t eat Brussels sprouts.”
 
Google Books
A Prairie Home Companion’s
Pretty Good Joke Book
Introduction by Garrison Keillor
Minneapolis, MN: HighBridge Company
2005
Pg. 160:
What’s the difference between boogers and broccoli?
Kids won’t eat broccoli.
 
Google Books
The Mammoth Book of Really Silly Jokes
By Geoff Tibballs
London: Constable & Robinson Ltd.
2011
Pg. 114:
What’s the difference between boogers and broccoli?
Kids won’t eat broccoli.
 
Google Books
Blonde Walks into a Bar:
The 4,000 Most Hilarious, Gut-Busting Jokes on Everything From Hung-Over Accountants to Horny Zebras
By Jonathan Swan
Berkeley, CA: Ulysses Press
2014
Pg. ?:
What’s the difference between boogers and broccoli?
Kids don’t eat broccoli.