| 年份 | 尼日尔 |
|---|---|
| 2023 | - |
| 2022 | 0.485853 |
| 2021 | 0.491112 |
| 2020 | 0.492775 |
| 2019 | 0.489188 |
| 2018 | 0.481743 |
| 2017 | 0.474449 |
| 2016 | 0.467442 |
| 2015 | 0.460841 |
| 2014 | 0.454446 |
| 2013 | 0.448503 |
| 2012 | 0.443277 |
| 2011 | 0.438494 |
| 2010 | 0.433856 |
| 2009 | 0.42957 |
| 2008 | 0.425395 |
| 2007 | 0.421273 |
| 2006 | 0.417831 |
| 2005 | 0.41546 |
| 2004 | 0.414102 |
| 2003 | 0.414 |
| 2002 | 0.414825 |
| 2001 | 0.415582 |
| 2000 | 0.415851 |
| 1999 | 0.415564 |
| 1998 | 0.414764 |
| 1997 | 0.413335 |
| 1996 | 0.411217 |
| 1995 | 0.408287 |
| 1994 | 0.404224 |
| 1993 | 0.398926 |
| 1992 | 0.392773 |
| 1991 | 0.385943 |
| 1990 | 0.378457 |
| 1989 | 0.370573 |
| 1988 | 0.362675 |
| 1987 | 0.354757 |
| 1986 | 0.346666 |
| 1985 | 0.338202 |
| 1984 | 0.32908 |
| 1983 | 0.318555 |
| 1982 | 0.307157 |
| 1981 | 0.296891 |
| 1980 | 0.288731 |
| 1979 | 0.282747 |
| 1978 | 0.279924 |
| 1977 | 0.279929 |
| 1976 | 0.279746 |
| 1975 | 0.277321 |
| 1974 | 0.273179 |
| 1973 | 0.267439 |
| 1972 | 0.259201 |
| 1971 | 0.248747 |
| 1970 | 0.235949 |
| 1969 | 0.219615 |
| 1968 | 0.198342 |
| 1967 | 0.173713 |
| 1966 | 0.150025 |
| 1965 | 0.130155 |
| 1964 | 0.115273 |
| 1963 | 0.107804 |
| 1962 | 0.107653 |
| 1961 | 0.109754 |
| 1960 | 0.111083 |