| 年份 | 乍得 |
|---|---|
| 2023 | - |
| 2022 | 3.9782 |
| 2021 | 4.01494 |
| 2020 | 4.05306 |
| 2019 | 4.068 |
| 2018 | 4.06839 |
| 2017 | 4.07491 |
| 2016 | 4.08538 |
| 2015 | 4.09565 |
| 2014 | 4.15371 |
| 2013 | 4.25515 |
| 2012 | 4.34606 |
| 2011 | 4.44 |
| 2010 | 4.53634 |
| 2009 | 4.63356 |
| 2008 | 4.74533 |
| 2007 | 4.86424 |
| 2006 | 4.98342 |
| 2005 | 5.1117 |
| 2004 | 5.26132 |
| 2003 | 5.42999 |
| 2002 | 5.57537 |
| 2001 | 5.68869 |
| 2000 | 5.79343 |
| 1999 | 5.91053 |
| 1998 | 6.03504 |
| 1997 | 6.13989 |
| 1996 | 6.23008 |
| 1995 | 6.39455 |
| 1994 | 6.57617 |
| 1993 | 6.60955 |
| 1992 | 6.64397 |
| 1991 | 6.81464 |
| 1990 | 6.94365 |
| 1989 | 7.00083 |
| 1988 | 7.10548 |
| 1987 | 7.21644 |
| 1986 | 7.33392 |
| 1985 | 7.40067 |
| 1984 | 7.29481 |
| 1983 | 7.21421 |
| 1982 | 7.43824 |
| 1981 | 7.66848 |
| 1980 | 7.48754 |
| 1979 | 7.31738 |
| 1978 | 7.31326 |
| 1977 | 7.28656 |
| 1976 | 7.2632 |
| 1975 | 7.25345 |
| 1974 | 7.25844 |
| 1973 | 7.26879 |
| 1972 | 7.27707 |
| 1971 | 7.28652 |
| 1970 | 7.29687 |
| 1969 | 7.30372 |
| 1968 | 7.31183 |
| 1967 | 7.32143 |
| 1966 | 7.32967 |
| 1965 | 7.33731 |
| 1964 | 7.31737 |
| 1963 | 7.27306 |
| 1962 | 7.23583 |
| 1961 | 7.2112 |
| 1960 | 7.21026 |