From this article on msnbc.com:
The president of the humor society, British sociologist Christie Davies, offered insights Tuesday on the state of humor in today's world.
Among other things, he said, jokes in eastern Europe were a lot better when the communists ran the show.
"Once you have a democracy with free speech, you have fewer jokes," said Davies, an emeritus professor at the University of Reading, in England. "Jokes, in many ways, are a way of getting around restrictions on what you can say. That was a very important factor in eastern Europe."