| 年份 | 乍得 |
|---|---|
| 2023 | - |
| 2022 | 2.74435 |
| 2021 | 2.82204 |
| 2020 | 2.84591 |
| 2019 | 3.00824 |
| 2018 | 3.11722 |
| 2017 | 3.09025 |
| 2016 | 2.93936 |
| 2015 | 2.99972 |
| 2014 | 3.41038 |
| 2013 | 3.42078 |
| 2012 | 3.37467 |
| 2011 | 3.40597 |
| 2010 | 3.34314 |
| 2009 | 3.47628 |
| 2008 | 3.40365 |
| 2007 | 3.34368 |
| 2006 | 3.49858 |
| 2005 | 3.94955 |
| 2004 | 4.39386 |
| 2003 | 3.92845 |
| 2002 | 3.40728 |
| 2001 | 3.28795 |
| 2000 | 3.3724 |
| 1999 | 3.43509 |
| 1998 | 3.36514 |
| 1997 | 3.38023 |
| 1996 | 4.3796 |
| 1995 | 4.34768 |
| 1994 | 2.17875 |
| 1993 | 2.06005 |
| 1992 | 3.95203 |
| 1991 | 3.36109 |
| 1990 | 2.45802 |
| 1989 | 3.10227 |
| 1988 | 3.11948 |
| 1987 | 3.25199 |
| 1986 | 2.7314 |
| 1985 | 0.701063 |
| 1984 | 1.00572 |
| 1983 | 4.74087 |
| 1982 | 4.48732 |
| 1981 | -0.217831 |
| 1980 | -0.119787 |
| 1979 | 1.81724 |
| 1978 | 0.550036 |
| 1977 | 0.66195 |
| 1976 | 0.838034 |
| 1975 | 1.05122 |
| 1974 | 1.25631 |
| 1973 | 1.38392 |
| 1972 | 1.26228 |
| 1971 | 1.18214 |
| 1970 | 1.19431 |
| 1969 | 1.176 |
| 1968 | 1.16204 |
| 1967 | 1.17981 |
| 1966 | 1.23541 |
| 1965 | 1.32797 |
| 1964 | 1.56799 |
| 1963 | 1.64093 |
| 1962 | 1.64501 |
| 1961 | 1.64174 |
| 1960 | - |