Europe has a new source of economic growth. In the next few months all European Union countries that do not already include drugs, prostitution and other illegal and gray-market businesses in their gross domestic product calculations will have to do so.

The 2010 version of the European System of Accounts becomes obligatory for GDP reporting by EU member states in September. It states unequivocally that "illegal economic actions shall be considered as transactions when all units involved enter the actions by mutual agreement. Thus, purchases, sales or barters of illegal drugs or stolen property are transactions, while theft is not."

The ostensible goal is to make countries' economic data comparable. Relatively permissive EU members such as Germany, Hungary, Austria and Greece, where prostitution is legal, already include the revenue it produces in their national accounts. Other countries with more prudish laws have been denied a statistical bonus.