| 年份 | 乍得 |
|---|---|
| 2023 | - |
| 2022 | 1.46105 |
| 2021 | 1.44871 |
| 2020 | 1.43737 |
| 2019 | 1.42453 |
| 2018 | 1.41249 |
| 2017 | 1.40389 |
| 2016 | 1.39826 |
| 2015 | 1.3953 |
| 2014 | 1.37305 |
| 2013 | 1.33906 |
| 2012 | 1.3141 |
| 2011 | 1.29084 |
| 2010 | 1.27007 |
| 2009 | 1.28106 |
| 2008 | 1.31466 |
| 2007 | 1.33849 |
| 2006 | 1.36244 |
| 2005 | 1.38703 |
| 2004 | 1.41645 |
| 2003 | 1.45256 |
| 2002 | 1.49148 |
| 2001 | 1.53113 |
| 2000 | 1.57146 |
| 1999 | 1.61294 |
| 1998 | 1.65527 |
| 1997 | 1.69731 |
| 1996 | 1.74036 |
| 1995 | 1.79297 |
| 1994 | 1.84646 |
| 1993 | 1.8801 |
| 1992 | 1.91304 |
| 1991 | 1.9647 |
| 1990 | 2.01255 |
| 1989 | 2.05233 |
| 1988 | 2.10032 |
| 1987 | 2.14969 |
| 1986 | 2.19713 |
| 1985 | 2.23177 |
| 1984 | 2.23567 |
| 1983 | 2.23796 |
| 1982 | 2.2835 |
| 1981 | 2.32629 |
| 1980 | 2.309 |
| 1979 | 2.29549 |
| 1978 | 2.30906 |
| 1977 | 2.32104 |
| 1976 | 2.3355 |
| 1975 | 2.35368 |
| 1974 | 2.37661 |
| 1973 | 2.40426 |
| 1972 | 2.43399 |
| 1971 | 2.45959 |
| 1970 | 2.47781 |
| 1969 | 2.48934 |
| 1968 | 2.49279 |
| 1967 | 2.49156 |
| 1966 | 2.49492 |
| 1965 | 2.50982 |
| 1964 | 2.53679 |
| 1963 | 2.57782 |
| 1962 | 2.62683 |
| 1961 | 2.66483 |
| 1960 | 2.67849 |