| 年份 | 乍得 |
|---|---|
| 2023 | - |
| 2022 | 3.90329 |
| 2021 | 3.98725 |
| 2020 | 4.05311 |
| 2019 | 4.09617 |
| 2018 | 4.13608 |
| 2017 | 4.16802 |
| 2016 | 4.18071 |
| 2015 | 4.17416 |
| 2014 | 4.15573 |
| 2013 | 4.11938 |
| 2012 | 4.07338 |
| 2011 | 4.03706 |
| 2010 | 4.01457 |
| 2009 | 3.996 |
| 2008 | 3.97751 |
| 2007 | 3.96036 |
| 2006 | 3.94132 |
| 2005 | 3.91563 |
| 2004 | 3.8781 |
| 2003 | 3.82856 |
| 2002 | 3.78566 |
| 2001 | 3.755 |
| 2000 | 3.7308 |
| 1999 | 3.70968 |
| 1998 | 3.69436 |
| 1997 | 3.68775 |
| 1996 | 3.68862 |
| 1995 | 3.67737 |
| 1994 | 3.60568 |
| 1993 | 3.53977 |
| 1992 | 3.50065 |
| 1991 | 3.42136 |
| 1990 | 3.35935 |
| 1989 | 3.40241 |
| 1988 | 3.48677 |
| 1987 | 3.53983 |
| 1986 | 3.58458 |
| 1985 | 3.63491 |
| 1984 | 3.72907 |
| 1983 | 3.82232 |
| 1982 | 3.85129 |
| 1981 | 3.88879 |
| 1980 | 4.00878 |
| 1979 | 4.11907 |
| 1978 | 4.19242 |
| 1977 | 4.26736 |
| 1976 | 4.34 |
| 1975 | 4.40967 |
| 1974 | 4.47465 |
| 1973 | 4.53376 |
| 1972 | 4.59033 |
| 1971 | 4.64506 |
| 1970 | 4.69838 |
| 1969 | 4.75252 |
| 1968 | 4.80775 |
| 1967 | 4.86196 |
| 1966 | 4.90824 |
| 1965 | 4.94222 |
| 1964 | 4.9654 |
| 1963 | 4.97826 |
| 1962 | 4.98289 |
| 1961 | 4.98764 |
| 1960 | 4.99746 |