Here in Brussels, farmers are demonstrating about the high prices of diesel and fertiliser, and the capital of European bureaucracy is still pondering the consequences of the Irish rejection of the Lisbon treaty. But Europe does have something to celebrate – the euro has just turned ten.

Given some of the reservations, including my own, about the long-term prospects for the currency, just being around might be considered an achievement, but it has done more than survive. It is now the strongest major currency in the world, and the eurozone has had reasonable growth and employment for the past decade. Not bad at all. But maybe these have been easy years for the euro. Maybe tougher times for the currency lie ahead.

First, the score card. If you compare the performance of the world's three largest currencies since 2000, there is no question which has become most favoured. The euro initially lost ground against the dollar, but since 2002 it has been stable, with the dollar gradually deteriorating. The yen has been the weakest currency.

Another measure of the euro's status is the extent to which global central banks hold it in their reserves. It accounted for 26.5% of the total last year and the proportion is rising. If countries that now peg their currencies to the dollar shift to different currencies, that will rise further.

So the euro has become "sound money for the world". That phrase is taken from a new Goldman Sachs paper that calibrates its progress and makes some judgements about its future, one of which is that Britain is unlikely to join for the foreseeable future.

Growth per head of population has been as fast in the eurozone as in the US, something not many people realise. The eurozone has actually created more new jobs over the past decade than the US. But relative growth performance is not simply a function of the currency. Other policies, including regulation and tax, are just as important.

The central point is that the euro has achieved the main objectives needed to secure its place as a reliable global currency. It is perceived as being well-managed, and the reputation of the European Central Bank is now as solid as that of the US Federal Reserve or the Bank of England.

But arguably these were easy times. What happens next? Well, Goldman admits the possibility that some countries might leave the eurozone. The paper makes a point I have not seen before: that it would be easier for a country to leave the zone if its economy were strong than if it were weak. In other words, it would be easier to revalue out of it than to devalue out of it.

But would Germany really dump the euro? Or Ireland? Surely not. Investors buying long bonds are making assumptions, not just that the currency will be around in 30 years but also that the institutions behind it will not allow a rapid depreciation during that time. This currency union looks solid because it is backed by the discipline of an independent central bank and the fiscal structure of European Monetary Union. So Goldman's conclusion is that the euro is secure for the foreseeable future.

That said, the next few years are going to be bumpy. The European economy will slow further. Yet interest rates seem likely to rise next month. That will cause a stir, particularly in Spain and Ireland, where housing markets are facing pressure. I still think the real test of the euro will come in the next cycle, perhaps 10 years away, rather than this one. But, meanwhile, expect even more tension.