| 年份 | 乍得 |
|---|---|
| 2023 | - |
| 2022 | 3.7884 |
| 2021 | 3.87122 |
| 2020 | 3.93751 |
| 2019 | 3.98284 |
| 2018 | 4.02492 |
| 2017 | 4.05885 |
| 2016 | 4.07376 |
| 2015 | 4.0703 |
| 2014 | 4.05398 |
| 2013 | 4.0159 |
| 2012 | 3.96676 |
| 2011 | 3.92642 |
| 2010 | 3.89932 |
| 2009 | 3.87694 |
| 2008 | 3.85464 |
| 2007 | 3.83569 |
| 2006 | 3.81693 |
| 2005 | 3.79138 |
| 2004 | 3.75144 |
| 2003 | 3.69629 |
| 2002 | 3.64996 |
| 2001 | 3.61864 |
| 2000 | 3.59383 |
| 1999 | 3.57035 |
| 1998 | 3.55087 |
| 1997 | 3.53916 |
| 1996 | 3.53353 |
| 1995 | 3.50721 |
| 1994 | 3.42914 |
| 1993 | 3.38601 |
| 1992 | 3.37541 |
| 1991 | 3.31461 |
| 1990 | 3.27863 |
| 1989 | 3.34493 |
| 1988 | 3.43371 |
| 1987 | 3.48863 |
| 1986 | 3.53132 |
| 1985 | 3.57864 |
| 1984 | 3.68262 |
| 1983 | 3.78393 |
| 1982 | 3.79414 |
| 1981 | 3.80753 |
| 1980 | 3.92919 |
| 1979 | 4.03635 |
| 1978 | 4.08791 |
| 1977 | 4.13943 |
| 1976 | 4.19135 |
| 1975 | 4.24584 |
| 1974 | 4.30081 |
| 1973 | 4.35688 |
| 1972 | 4.41767 |
| 1971 | 4.47847 |
| 1970 | 4.53541 |
| 1969 | 4.59096 |
| 1968 | 4.64426 |
| 1967 | 4.69467 |
| 1966 | 4.74324 |
| 1965 | 4.78953 |
| 1964 | 4.83374 |
| 1963 | 4.87801 |
| 1962 | 4.92118 |
| 1961 | 4.95867 |
| 1960 | 4.98746 |