| ANNEE | MAXIMUM | MINIMUM |
| 2023 | 1.781 | 1.651 |
| 2022 | 1.75 | 0.71 |
| 2021 | 2.39 | -0.09 |
| 2020 | 2.76 | 0.24 |
| 2019 | 3.39 | 0.36 |
| 2018 | 2.81 | 0.16 |
| 2017 | 3.38 | 0.17 |
| 2016 | 2.43 | -0.39 |
| 2015 | 1.68 | -0.12 |
| 2014 | 2.82 | 0.14 |
| 2013 | 2.02 | -0.05 |
| 2012 | 2.366 | -0.615 |
| 2011 | 2.92 | 0.041 |
| 2010 | 1.7 | -0.38 |
| 2009 | 2.65 | -0.06 |
| 2008 | 3.04 | 0.01 |
| 2007 | 2.48 | -0.59 |
| 2006 | 2.18 | -0.03 |
| 2005 | 2.81 | -0.32 |
| 2004 | 1.82 | -0.11 |
| 2003 | 2.03 | -0.36 |
| 2002 | 2.19 | -0.43 |
| 2001 | 2.37 | -0.52 |
| 2000 | 2.02 | -0.38 |
| 1999 | 1.95 | -0.33 |
| 1998 | 3.6 | -0.31 |
| 1997 | 2.96 | 0.35 |
| 1996 | 2.62 | 0.44 |
| 1995 | 2.21 | -0.21 |
| 1994 | 2.55 | 0.13 |
| 1993 | 3.91 | 0.36 |
| 1992 | 2.39 | 0.22 |
| 1991 | 3.06 | -0.12 |
| 1990 | 2.27 | 0.15 |
| 1989 | 1.8 | 0 |
| 1988 | 2.14 | 0 |
| 1987 | 2.85 | 0.11 |
| 1986 | 2.52 | 0.58 |
| 1985 | 2.49 | 0.32 |
| 1984 | 3.07 | 0.26 |
| 1983 | 3.21 | 0.29 |
| 1982 | 2.51 | 0.25 |
| 1981 | 3.5 | 0.53 |
| 1980 | 2.42 | 0.51 |
| 1979 | 2.85 | 0.55 |
| 1978 | 3 | 0.06 |
| 1977 | 2.86 | 0.24 |
| 1976 | 4.35 | 0.47 |
| 1975 | 2.98 | 0.46 |
| 1974 | 3.62 | 0.76 |
| 1973 | 3.79 | 0.9 |
| 1972 | 3.28 | 0.58 |
| 1971 | 3.44 | 0.09 |
| 1970 | 2.49 | 0.47 |
| 1969 | 2.95 | 0.31 |
| 1968 | 4.06 | 0.31 |
| 1967 | 3.01 | 0.06 |
| 1966 | 3.68 | -0.01 |
| 1965 | 1.89 | -0.45 |
| 1964 | 2.59 | -0.57 |
| 1963 | 2.81 | -0.32 |
| 1962 | 3.04 | -0.25 |
| 1961 | 0.87 | -0.08 |
