In terms of relative unit wage costs, Germany's competitiveness has improved by around 13% since the euro started.

ECONOMIST: In place of devaluation, troubled members could try reform

The combination of a 24% rise in the yuan against the dollar and a 21% increase in Chinese unit labour costs, relative to America's, explains the steep appreciation shown in the chart.

ECONOMIST: The yuan-dollar exchange rate

Over the long term, higher productivity growth and better-functioning labour markets are vital if economies in southern Europe are to regain the competitive ground they lost in the first decade of monetary union, when their unit labour costs soared relative to those in northern countries like Germany.

ECONOMIST: Free exchange

Zurich moved to the top of the list for the first time in at least two decades in part because of the surge in the Swiss franc over the past year, which made goods there more expensive relative to elsewhere, the Economist Intelligence Unit said.

WSJ: Zurich Is World's Costliest City

For the average industry, the average company, we can make huge progress on solar, we can make huge progress on wind, but the unit costs -- energy costs that you get from those technologies relative to coal are still going to be pretty substantial.

WHITEHOUSE: President Obama Holds a Town Hall in New Hampshire

The unit labour costs that is, the amount that had to be paid for labour relative to the value of the goods produced with it.

FORBES: The German Labour Miracle

The carbon dioxide intensity of U.S. energy supply (CO2 per unit of energy) in 2009 also dropped as a result of lower natural gas prices relative to coal.

FORBES: U.S. Carbon Emissions Plunge

The study, remember, argues that a doubling of the relative wages of civil servants is needed to reduce a country's score on the corruption index by a single unit.

ECONOMIST: Reasons to be venal