Because it's not a member of the European Union. It's a combination of all similar organizations in the European Union. It is informed of decisions, it is solicited, and it sometimes takes part in processes. That was the case in the investigation of SWIFT, the personal information analysis and credit business. However, it still lags behind. It is not a participant in what is really the authority where privacy matters are considered, evaluated and decided.
On May 15th, 2008. See this statement in context.