More evidence: Markets work

Marginal incentives:

As the credit crunch bites, Britons may be turning to sex as a cheap way to pass the time, a charity says.
A YouGov survey of 2,000 adults found sex was the most popular free activity, ahead of window shopping and gossiping.
The Scots were most amorous with 43% choosing sex over other pastimes, compared with 35% in South England. . . .
Around one in 10 respondents to the survey, carried in November, said their favourite free activity was window shopping and 6% chose going to a museum as the cheapest way to pass the time.

Hmmm. Maybe this explains why my wife and I -- who came of age during the recession-plagued '70s -- have six kids. The U.S. economy has been in recession since 2007. Get busy, people!