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June 1846 – February 1878
February 1878 – July 1903
August 1903 – August 1914
September 1914 – January 1922
February 1922 – February 1939
March 1939 – October 1958
October 1958 – June 1963
June 1963 – August 1978
August 1978 – September 1978
October 1978 – April 2005
April 2005 – February 2013
since March 2013