Average length of EUCO membership for leaders

The chart below shows the average duration of European Council membership (in years) for the leaders of each Member State. There are significant variations between Member States, reflecting the electoral cycle and frequency of changes in leadership in the country concerned since its accession to the EU (or since the European Council was established in 1975, for the first nine Member States).
Whereas the leaders of some Member States have, on average, each spent barely two years in the European Council, the leaders of others have spent four or five times as long in the institution. The average tenure of German chancellors and Luxembourgish prime ministers has been over nine years, whereas the Bulgarian, Czech and Italian prime ministers have served for an average of less than two years.