| 年份 | 乍得 |
|---|---|
| 2023 | - |
| 2022 | 3.11502 |
| 2021 | 3.16389 |
| 2020 | 3.16053 |
| 2019 | 3.29458 |
| 2018 | 3.37813 |
| 2017 | 3.32459 |
| 2016 | 3.14865 |
| 2015 | 3.1841 |
| 2014 | 3.56999 |
| 2013 | 3.55702 |
| 2012 | 3.48763 |
| 2011 | 3.49445 |
| 2010 | 3.40849 |
| 2009 | 3.51855 |
| 2008 | 3.44589 |
| 2007 | 3.38719 |
| 2006 | 3.54078 |
| 2005 | 3.99175 |
| 2004 | 4.43603 |
| 2003 | 3.9706 |
| 2002 | 3.44814 |
| 2001 | 3.33008 |
| 2000 | 3.4145 |
| 1999 | 3.47717 |
| 1998 | 3.40721 |
| 1997 | 3.42099 |
| 1996 | 4.42164 |
| 1995 | 4.38969 |
| 1994 | 2.21947 |
| 1993 | 2.27995 |
| 1992 | 4.22081 |
| 1991 | 3.62918 |
| 1990 | 2.72158 |
| 1989 | 3.3639 |
| 1988 | 3.37918 |
| 1987 | 3.50726 |
| 1986 | 2.98602 |
| 1985 | 0.951328 |
| 1984 | 1.25533 |
| 1983 | 4.98616 |
| 1982 | 4.73077 |
| 1981 | 0.0225689 |
| 1980 | 0.120029 |
| 1979 | 2.05282 |
| 1978 | 1.75233 |
| 1977 | 1.79732 |
| 1976 | 1.91444 |
| 1975 | 2.06697 |
| 1974 | 2.2154 |
| 1973 | 2.28787 |
| 1972 | 2.16384 |
| 1971 | 2.02816 |
| 1970 | 1.98951 |
| 1969 | 1.92038 |
| 1968 | 1.8633 |
| 1967 | 1.8367 |
| 1966 | 1.85086 |
| 1965 | 1.90388 |
| 1964 | 1.94719 |
| 1963 | 1.95189 |
| 1962 | 1.94317 |
| 1961 | 1.9283 |
| 1960 | - |