| 年份 | 乍得 |
|---|---|
| 2023 | - |
| 2022 | 3.95272 |
| 2021 | 4.68312 |
| 2020 | 4.73538 |
| 2019 | 3.58751 |
| 2018 | 3.60339 |
| 2017 | 4.32522 |
| 2016 | 4.21169 |
| 2015 | 5.14509 |
| 2014 | 6.22583 |
| 2013 | 7.92416 |
| 2012 | 6.87615 |
| 2011 | 6.48381 |
| 2010 | 6.73529 |
| 2009 | 7.59312 |
| 2008 | 6.26677 |
| 2007 | 5.99965 |
| 2006 | 4.57324 |
| 2005 | 4.1574 |
| 2004 | 4.90859 |
| 2003 | 7.58791 |
| 2002 | 7.70537 |
| 2001 | 7.48995 |
| 2000 | 7.71826 |
| 1999 | 6.92631 |
| 1998 | 5.62853 |
| 1997 | 6.52731 |
| 1996 | 7.89558 |
| 1995 | 7.26866 |
| 1994 | 8.0757 |
| 1993 | 10.0473 |
| 1992 | 9.19818 |
| 1991 | 8.91343 |
| 1990 | 10.046 |
| 1989 | 15.0456 |
| 1988 | 12.7068 |
| 1987 | 15.8257 |
| 1986 | 13.9063 |
| 1985 | 11.7459 |
| 1984 | 10.0165 |
| 1983 | 6.05034 |
| 1982 | 5.47088 |
| 1981 | - |
| 1980 | - |
| 1979 | - |
| 1978 | 17.8587 |
| 1977 | 16.8974 |
| 1976 | 16.6608 |
| 1975 | 17.7942 |
| 1974 | 19.3935 |
| 1973 | 21.6966 |
| 1972 | 19.5112 |
| 1971 | 19.2571 |
| 1970 | 18.7104 |
| 1969 | 17.7463 |
| 1968 | 16.3812 |
| 1967 | 15.73 |
| 1966 | 14.639 |
| 1965 | 13.7602 |
| 1964 | 13.5831 |
| 1963 | 13.4133 |
| 1962 | 13.1794 |
| 1961 | 12.6685 |
| 1960 | 12.6254 |