Economics focus: Exports to Mars | The Economist
http://www.economist.com/node/21538100
In theory, countries’ current-account balances should all sum to zero because one country’s export is another’s import. However, if you add up all countries’ reported current-account transactions (exports minus imports of goods and services, net investment income, workers’ remittances and other transfers), the world exported $331 billion more than it imported in 2010, according to the IMF’s World Economic Outlook. The fund forecasts that the global current-account surplus will rise to almost $700 billion by 2014.