| | | | | | | | | | | 1971 3 | 1990 8 1997 11 | | | | 1990 . 08 1992 . 05 | | 1992 . 05 1994 . 05 | | 1994 . 05 1997 . 02 | | 1997 . 02 2001 . 12 | | 1997 . 12 | 1998 . 08 2000 . 12 | | 2001 . 12 2002 . 04 | | 2002 . 04 2008 . 08 | | 2008 . 08 2012 . 08 | 2008 . 08 2011 . 01 | | 2012 . 08 2015 . 12 | | 2015 . 12 2018 . 09 | | 2018 . 09 2021 . 02 | | | 2021 . 02 2021 . 06 | | 2021 . 06 2021 . 07 | | | 2021 . 07 | | | | | | | | | |