Gross domestic product (GDP) is the value of all the goods and services produced by a country.
This chart shows how much GDP has grown, or contracted, every year since the launch of the euro.
It shows very clearly the damage caused to the whole of the eurozone by the financial crisis.
Notice that while Portugal did not experience a huge dip in 2009, its GDP growth was relatively low for much of the previous decade, which made the big infrastructure projects it was pursuing difficult to afford.
The chart shows data for all of the countries that officially use the euro as well as the UK, which is included to allow for comparisons.
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