The drowning lawyer (or lawyers) joke has been one of the most popular of lawyer jokes. THe following joke has been cited in print since at least 1994:
 
Q: What do you throw to a drowning lawyer?
A: His partners!
 
Another drowning lawyer joke is, “How do you save a drowning lawyer? Take your foot off his head.”
     
 
Google Groups: rec.humor
Request: Lawyer jokes file
Dan Sobel
12/27/94
(...)
Q: What do you throw to a drowning lawyer?
A: His partners!
   
Google Groups: rec.humor
Lawyer jokes wanted
Bobby H
2/17/96
(...)
Q. What do you throw a drowning lawyer?
A. His partners.
 
Google Books
A Collection of Jokes and Funny Stories
By Marvin Lebman
Victoria, BC: Trafford Publishing
2004
Pg. 280:
What do you throw to a drowning lawyer? His partners.
 
Google Books
The World’s Funniest Lawyer Jokes:
A Caseload of Jurisprudential Jest
By Steven D. Price
New York, NY: SKyhorse Publishing
2011
Pg. ?:
Q: What do you throwtoa drowning lawyer?
A: His partners.
 
Google Books
The Good Wife and Philosophy:
Temptations of Saint Alicia
Edited by Kimberly Baltzer-Jaray and Robert Arp
Chicago, IL: Open Court Publishing Company
2013
Pg. ?:
Q: What do you throw to a drowning lawyer?
A: His partners.
 
Twitter
Reid Bryce Robbins
‏@reidbryce
Q: What do you throw to a drowning lawyer?
A: His partners.
3:50 PM - 5 Aug 2014