from a google search on language regime European parliament:
a thesis on the EU language regime (addresses both translation and interpretation) Quotes follow from this thesis:
"The Interpreting Directorate of the European Parliament employs approximately 240 permanent staff interpreters and relies on a reserve of more than 1000 auxiliary conference interpreters, of whom between 200 and 500 must be recruited each day to cover its needs. In 2002, the total volume of activity represented 56000 interpreter days for the European Parliament organs alone. Staff interpreters accounted for ± 50% of these working days, the remainder being provided by auxiliary conference interpreters. (Europa: Gateway to the European Union)"
"According to the official website of the European Commission, in 2004, the twenty official languages of the European Union are: Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hungarian, Italian, Latvian, Lithuanian, Maltese, Polish, Portuguese, Slovak, Slovene, Spanish and Swedish (Europa: Gateway to the European Union). The website provides elaborate information and detailed figures on the official languages in 199815, indicating the weight and importance of each language according to various data and inquiries."
Somewhere, this person got the idea that Esperanto is being used by many people within the EU institutions. Maybe I was in the wrong places or talking to the wrong people to find this out? People whom I met that were completely unassociated with the EU and interpreting would sometimes ask me about Esperanto when they found out what I was doing, but the word never arose in any of the fieldwork.