| Year | Value | | 2021 | 67.571014323773 | | 2020 | 73.936783515286 | | 2019 | 60.844039717462 | | 2018 | 65.965314737097 | | 2001 | 69.099798093858 | | 2000 | 78.41832770873 | | 1999 | 83.914497696666 | | 1998 | 71.575334045205 | | 1997 | 54.627578692248 | | 1996 | 49.479632030574 | | 1995 | 37.071282676527 | | 1994 | 51.434529837839 | | 1993 | 41.44153010332 | | 1992 | 20.621673383358 |
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