This might come as a bit of a shock to the Dollar-is-history-as-a-reserve-currency crowd.  Heck, I'm not one of those dollar-collapse guys, and it came as a surprise to me.

From the ECB via Alea blog.

The use of the euro in foreign exchange reserves held by third countries, i.e. countries outside the euro area, increased moderately by around 1½ percentage points during the review period owing to positive valuation effects. When measured at constant exchange rates, the share of the euro in global foreign reserves decreased slightly by almost 1 percentage point, mainly as a result of a decline in developing countries. ...

[The euro's] role gradually increased during the first few years of European Monetary Union but has been broadly stable for around five years.

Over those five years, the value of the euro has soared relative to the dollar, yet it has not been due to central bank buying of the euro.  One of the tenants of the dollar-collapse crowd was that central banks would dump dollars and buy other currencies.  That appears not to have happened.