| 年份 | 尼日尔 |
|---|---|
| 2023 | - |
| 2022 | 0.329047 |
| 2021 | 0.336955 |
| 2020 | 0.341344 |
| 2019 | 0.340583 |
| 2018 | 0.335486 |
| 2017 | 0.329969 |
| 2016 | 0.324852 |
| 2015 | 0.320035 |
| 2014 | 0.31517 |
| 2013 | 0.310794 |
| 2012 | 0.30711 |
| 2011 | 0.303735 |
| 2010 | 0.300505 |
| 2009 | 0.297413 |
| 2008 | 0.294504 |
| 2007 | 0.291764 |
| 2006 | 0.289589 |
| 2005 | 0.288255 |
| 2004 | 0.287669 |
| 2003 | 0.2878 |
| 2002 | 0.288557 |
| 2001 | 0.289264 |
| 2000 | 0.289289 |
| 1999 | 0.288671 |
| 1998 | 0.287348 |
| 1997 | 0.285172 |
| 1996 | 0.282488 |
| 1995 | 0.279417 |
| 1994 | 0.275934 |
| 1993 | 0.272332 |
| 1992 | 0.268713 |
| 1991 | 0.2648 |
| 1990 | 0.260237 |
| 1989 | 0.25508 |
| 1988 | 0.249505 |
| 1987 | 0.243662 |
| 1986 | 0.23783 |
| 1985 | 0.232153 |
| 1984 | 0.226704 |
| 1983 | 0.221425 |
| 1982 | 0.216072 |
| 1981 | 0.209944 |
| 1980 | 0.202538 |
| 1979 | 0.193785 |
| 1978 | 0.183121 |
| 1977 | 0.171104 |
| 1976 | 0.159904 |
| 1975 | 0.15083 |
| 1974 | 0.143911 |
| 1973 | 0.139908 |
| 1972 | 0.138548 |
| 1971 | 0.137218 |
| 1970 | 0.134089 |
| 1969 | 0.129081 |
| 1968 | 0.121763 |
| 1967 | 0.112134 |
| 1966 | 0.10256 |
| 1965 | 0.0949953 |
| 1964 | 0.0896384 |
| 1963 | 0.0870543 |
| 1962 | 0.0873214 |
| 1961 | 0.0883756 |
| 1960 | 0.0886216 |