| 年份 | 尼日尔 |
|---|---|
| 2023 | - |
| 2022 | 2.41086 |
| 2021 | 2.43861 |
| 2020 | 2.46781 |
| 2019 | 2.49643 |
| 2018 | 2.523 |
| 2017 | 2.54641 |
| 2016 | 2.56606 |
| 2015 | 2.58303 |
| 2014 | 2.59678 |
| 2013 | 2.60747 |
| 2012 | 2.61646 |
| 2011 | 2.62404 |
| 2010 | 2.63063 |
| 2009 | 2.63646 |
| 2008 | 2.64158 |
| 2007 | 2.64635 |
| 2006 | 2.64973 |
| 2005 | 2.6505 |
| 2004 | 2.6421 |
| 2003 | 2.63131 |
| 2002 | 2.64837 |
| 2001 | 2.6983 |
| 2000 | 2.76421 |
| 1999 | 2.84658 |
| 1998 | 2.93261 |
| 1997 | 2.98109 |
| 1996 | 2.98584 |
| 1995 | 2.97037 |
| 1994 | 2.94422 |
| 1993 | 2.9133 |
| 1992 | 2.88192 |
| 1991 | 2.85169 |
| 1990 | 2.82257 |
| 1989 | 2.79459 |
| 1988 | 2.76929 |
| 1987 | 2.74794 |
| 1986 | 2.72945 |
| 1985 | 2.71334 |
| 1984 | 2.69946 |
| 1983 | 2.6854 |
| 1982 | 2.6717 |
| 1981 | 2.66233 |
| 1980 | 2.65877 |
| 1979 | 2.6594 |
| 1978 | 2.66336 |
| 1977 | 2.67 |
| 1976 | 2.67726 |
| 1975 | 2.68409 |
| 1974 | 2.6914 |
| 1973 | 2.70017 |
| 1972 | 2.70911 |
| 1971 | 2.71674 |
| 1970 | 2.72211 |
| 1969 | 2.72472 |
| 1968 | 2.72393 |
| 1967 | 2.72024 |
| 1966 | 2.71486 |
| 1965 | 2.70804 |
| 1964 | 2.69956 |
| 1963 | 2.68974 |
| 1962 | 2.6775 |
| 1961 | 2.65972 |
| 1960 | 2.63476 |