“What did the hot dog say when he crossed the finish line?”/“I’m the wiener!”

A hot dog “wiener” pun is:
 
Q: What did the hot dog say when he crossed the finish line?
A: “I’m the wiener!”
 
The joke has been cited in print since at least 1992.
 
   
8 March 1992, The Arizona Republic (Phoenix, AZ), Kids sec., pg. ?, col. 1:
What did the hot dog say when he crossed the finish line?
“I’m a wiener.”
—submitted by Robert A. Dolfo, 10, Phoenix
 
Google Groups: rec.humor
Qs&As
Nancy Carson
9/27/96
What did the hot dog say when he crossed the finish line? 
I’m the wiener!
 
22 November 2000, Indianapolis (IN) Star, “Early reason to give thanks” by Biil McCleery, pg. S1:
“What did the hot dog say as it crossed the finish line?” asked Alex Riggen, 11.
 
His audience appeared stumped.
 
“I’m the wiener!” Alex said.
 
Google Books
A Prairie Home Companion
Pretty Good Joke Book
By Brian Becker
Minneapolis, MN: HighBridge
2003
Pg. 60:
What did the hot dog say when he crossed the finish line?
I’m the wiener!
 
Google Groups: alt.humor.puns
Puns of the Weak 02-07-03
Stan Kegel
2/7/03
(...)
What did the hot dog say when it crossed the finish line?
I’m the weiner! (Daily Groaner)
   
Twitter
Chris Luth
@Chris_Luth
What did the hot dog say to the hamburger when he crossed the finish line?—— I’m the WIENER!  😊
7:21 AM - 27 May 2009
 
Twitter
Christa A. Nelson
@epiphanyvp
Joke on the wal @ the Flying Wieniel…  What did the hot dog say when he crossed the finish line?  “I’m a WIENER!”  LOL Boys love that 1!
4:52 PM - 20 Jun 2009
 
Google Books
Just Jokes a Collection of Kids Jokes
By Phyllis Agles-Johnson
Raleigh, NC: Lulu Publishing (Lulu.com)
2010
Pg. 32:
Q. What did the hot dog say when it crossed the finish line?
A. I’m a Weiner!
 
Twitter
BunniLuver
@BunniLuver
@Crystalmccahil boobee..haha. What did the hot dog say when he crossed the finish line? ‘I’m the wiener’.
12:47 AM - 18 Jan 2010