“What’s the difference between a lawyer and a vampire?” (lawyer joke)

A popular lawyer joke is:
 
Q: What’s the difference between a lawyer and a vampire?
A: A vampire only sucks blood at night.
 
The joke has been cited in print since at least 1990.
 
 
Google Groups: rec.bicycles
One last lawyer joke
Chris Dresden
3/13/90
After reading the 2 recent lawyer jokes I couldn’t resist.  I heard this
on “Car Talk” on NPR.
What’s the difference between vampires and lawyers?
 
Vampires only suck blood at night!
   
Google Groups: alt.tasteless.jokes
Lawyer Jokes
Ben Magid
11/8/92
(...)
Q. What’s the difference between a lawyer and a vampire?
A. A vampire only sucks blood at night.
   
Google Groups: rec.humor
Some tasteless lawyer jokes
David Isaacs
12/4/94
(...)
Q: What’s the difference between a lawyer and a vampire?
A: A vampire only sucks blood at night.
 
Google Books
Netscape & HTML Explorer
By Urban A. LeJeune and Jeff Duntemann
Scottsdale, AZ: Coriolis Group Books
1995
Pg. 419:
Q. What’s the difference between a lawyer and a vampire?
A. A vampire only sucks blood at night.
 
Google Books
The Joke’s On… Lawyers
By Stan D. Ross
Sydney: The Federation Press
1996
Pg. 34:
Q: What’s the difference between a lawyer and a vampire?
A: A vampire only sucks blood at night.
 
Google Books
The Lawyer’s Joke Book:
There Are Some Things a Rat Just Won’t Do
By John Patrick Dolan and Dale Irvin
Charleston, SC: Advantage Media Group
2008
Pg. 51:
What’s the difference between a lawyer and a vampire?
A vampire only sucks blood at night.
 
Google Books
The Mammoth Book of One-Liners
By Geoff Tibballs
London: Constable & Robinson Ltd
2012
Pg. ?:
What’s the difference between a lawyer and a vampire?
A vampire only sucks blood at night.