ECB Publications
The ECB has to publish reports on its activities at least quarterly - it does so on a monthly basis (Monthly Bulletin). The ECB also produces an Annual Report.
Annual Report

The Annual Report describes the activities of the ESCB and reports on monetary policy in the year under review. Via the ECB’s website you can download all the annual reports in the various languages of the member countries.
Economic Bulletin (formerly Monthly Bulletin)
The Economic Bulletin provides a comprehensive analysis of economic and monetary developments and interim updates on key indicators. Each issue includes other articles focusing on broader topics, as well as a statistical section.
Convergence report
The Convergence Reports fulfil the ECB's requirement to report to the Council of the European Union (the Council) at least once every two years – or at the request of a Member State with a derogation – “on the progress made in the fulfilment by the Member States of their obligations regarding the achievement of economic and monetary union”.
The same mandate has been given to the European Commission, and the two reports are submitted to the Council in parallel.
Other publications
The ECB also produces other publications. Some of them are translated into all official EU languages.