| Year | Value | | 2021 | 75.418885931603 | | 2020 | 77.377581460016 | | 2019 | 64.589278135641 | | 2018 | 59.10231140701 | | 2017 | 56.259720838916 | | 2016 | 53.738791388435 | | 2015 | 52.651157236083 | | 2000 | 39.639058383733 | | 1999 | 42.178031602736 | | 1998 | 44.65426177338 | | 1997 | 43.175545996656 | | 1996 | 44.229875918566 | | 1995 | 44.868618988634 | | 1994 | 44.816969743077 | | 1993 | 39.950772089851 | | 1992 | 36.902231097941 | | 1991 | 33.913590828735 | | 1990 | 32.397194957793 |
|