| 年份 | 尼日尔 |
|---|---|
| 2023 | - |
| 2022 | 0.261832 |
| 2021 | 0.262063 |
| 2020 | 0.262908 |
| 2019 | 0.261104 |
| 2018 | 0.256521 |
| 2017 | 0.252148 |
| 2016 | 0.247744 |
| 2015 | 0.243239 |
| 2014 | 0.238967 |
| 2013 | 0.235019 |
| 2012 | 0.230934 |
| 2011 | 0.227074 |
| 2010 | 0.223768 |
| 2009 | 0.220879 |
| 2008 | 0.218554 |
| 2007 | 0.216669 |
| 2006 | 0.215102 |
| 2005 | 0.213689 |
| 2004 | 0.212413 |
| 2003 | 0.211507 |
| 2002 | 0.210672 |
| 2001 | 0.209404 |
| 2000 | 0.207596 |
| 1999 | 0.205205 |
| 1998 | 0.202049 |
| 1997 | 0.198324 |
| 1996 | 0.194312 |
| 1995 | 0.189513 |
| 1994 | 0.184036 |
| 1993 | 0.178314 |
| 1992 | 0.172431 |
| 1991 | 0.166364 |
| 1990 | 0.159984 |
| 1989 | 0.153449 |
| 1988 | 0.146838 |
| 1987 | 0.140406 |
| 1986 | 0.134696 |
| 1985 | 0.129846 |
| 1984 | 0.12592 |
| 1983 | 0.122951 |
| 1982 | 0.12058 |
| 1981 | 0.117922 |
| 1980 | 0.114413 |
| 1979 | 0.10997 |
| 1978 | 0.104394 |
| 1977 | 0.0978866 |
| 1976 | 0.0909817 |
| 1975 | 0.0839441 |
| 1974 | 0.076751 |
| 1973 | 0.0691639 |
| 1972 | 0.0613803 |
| 1971 | 0.0539802 |
| 1970 | 0.0474516 |
| 1969 | 0.042286 |
| 1968 | 0.0393929 |
| 1967 | 0.0389148 |
| 1966 | 0.0393856 |
| 1965 | 0.0398565 |
| 1964 | 0.0403783 |
| 1963 | 0.0406578 |
| 1962 | 0.0407452 |
| 1961 | 0.0415433 |
| 1960 | 0.0439456 |