Drawing precise historical comparisons for the entire euro zone is challenging because of currency fluctuations before the single currency was introduced and because of incomplete or incompatible data from euro-zone members like Slovenia, which was not an independent country until 1991.
It's one of the factors that affects, actually, the outlook for the UK economy, has affected us over the last five years, affects us going forward, the challenges of having a currency union without certain institutional structures.
The Challenge Tower mode is a single-player option that includes 300 specific challenges of various difficulties providing currency rewards upon completion; players have the option of using in-game currency to bypass other difficult challenges, completing them later.
Ensuring that the Australian community is aware of the damaging impacts of juvenile detention is important in challenging the currency of "tough on crime" policies.
And Paris, in a rare challenge to Merkel in five years of currency travails, has staked its all on keeping Greece in the euro, dispatching experts to help Athens to write its reform manifesto and loudly campaigning for an agreement to rescue Greece.
Now it has also warned of currency headwinds, and that markets remain challenging, although it was trying to cut costs.
With Arnold's Spark Challenges, those points will be converted into a new type of currency called "spark points".
Now the Royal Canadian Mint is using one of the oldest forms of currency, gold, to attract software developers to its project, the MintChip Challenge, to transform the country's remaining coins into digital currency.
While it seems unlikely that Bitcoins will ever represent a full-scale challenge to regular money, they point to the rise of virtual currencies and changing definition of currency.
