| 年份 | 乍得 |
|---|---|
| 2023 | - |
| 2022 | 3.26406 |
| 2021 | 3.27631 |
| 2020 | 3.26845 |
| 2019 | 3.24838 |
| 2018 | 3.21441 |
| 2017 | 3.16971 |
| 2016 | 3.13162 |
| 2015 | 3.10743 |
| 2014 | 3.08709 |
| 2013 | 3.06642 |
| 2012 | 3.0477 |
| 2011 | 3.0293 |
| 2010 | 3.00895 |
| 2009 | 2.98684 |
| 2008 | 2.9611 |
| 2007 | 2.93512 |
| 2006 | 2.91005 |
| 2005 | 2.88505 |
| 2004 | 2.85746 |
| 2003 | 2.82711 |
| 2002 | 2.80649 |
| 2001 | 2.79826 |
| 2000 | 2.79779 |
| 1999 | 2.7578 |
| 1998 | 2.69617 |
| 1997 | 2.66121 |
| 1996 | 2.63471 |
| 1995 | 2.60039 |
| 1994 | 2.62599 |
| 1993 | 2.72139 |
| 1992 | 2.79005 |
| 1991 | 2.82773 |
| 1990 | 2.87156 |
| 1989 | 2.9306 |
| 1988 | 2.98749 |
| 1987 | 3.0515 |
| 1986 | 3.11276 |
| 1985 | 3.17068 |
| 1984 | 3.24117 |
| 1983 | 3.30023 |
| 1982 | 3.32039 |
| 1981 | 3.34219 |
| 1980 | 3.40531 |
| 1979 | 3.46842 |
| 1978 | 3.51886 |
| 1977 | 3.57402 |
| 1976 | 3.63053 |
| 1975 | 3.68683 |
| 1974 | 3.74291 |
| 1973 | 3.79924 |
| 1972 | 3.85644 |
| 1971 | 3.9116 |
| 1970 | 3.96265 |
| 1969 | 4.01137 |
| 1968 | 4.05825 |
| 1967 | 4.10224 |
| 1966 | 4.1398 |
| 1965 | 4.16817 |
| 1964 | 4.18793 |
| 1963 | 4.19978 |
| 1962 | 4.20531 |
| 1961 | 4.20958 |
| 1960 | 4.21578 |