| 年份 | 尼日尔 |
|---|---|
| 2023 | - |
| 2022 | 2.96854 |
| 2021 | 2.97025 |
| 2020 | 2.97808 |
| 2019 | 2.99218 |
| 2018 | 3.01334 |
| 2017 | 3.0423 |
| 2016 | 3.07677 |
| 2015 | 3.11333 |
| 2014 | 3.15099 |
| 2013 | 3.18811 |
| 2012 | 3.22078 |
| 2011 | 3.24895 |
| 2010 | 3.27447 |
| 2009 | 3.29547 |
| 2008 | 3.3116 |
| 2007 | 3.32421 |
| 2006 | 3.33354 |
| 2005 | 3.34061 |
| 2004 | 3.34647 |
| 2003 | 3.3515 |
| 2002 | 3.35593 |
| 2001 | 3.35855 |
| 2000 | 3.3579 |
| 1999 | 3.26524 |
| 1998 | 3.09869 |
| 1997 | 2.97163 |
| 1996 | 2.87604 |
| 1995 | 2.79682 |
| 1994 | 2.83463 |
| 1993 | 2.96096 |
| 1992 | 3.02948 |
| 1991 | 3.04886 |
| 1990 | 3.03838 |
| 1989 | 3.01194 |
| 1988 | 2.97611 |
| 1987 | 2.9377 |
| 1986 | 2.90319 |
| 1985 | 2.87381 |
| 1984 | 2.84851 |
| 1983 | 2.82935 |
| 1982 | 2.81757 |
| 1981 | 2.80941 |
| 1980 | 2.8018 |
| 1979 | 2.79456 |
| 1978 | 2.78699 |
| 1977 | 2.7794 |
| 1976 | 2.77612 |
| 1975 | 2.78031 |
| 1974 | 2.7912 |
| 1973 | 2.80854 |
| 1972 | 2.8308 |
| 1971 | 2.85334 |
| 1970 | 2.87279 |
| 1969 | 2.88949 |
| 1968 | 2.90379 |
| 1967 | 2.91613 |
| 1966 | 2.92913 |
| 1965 | 2.94413 |
| 1964 | 2.96091 |
| 1963 | 2.97895 |
| 1962 | 2.99785 |
| 1961 | 3.0159 |
| 1960 | 3.03187 |