| 序号 |
时间(年) |
数据(单位：-) |
| 1 |
2024 |
|
| 2 |
2023 |
|
| 3 |
2022 |
|
| 4 |
2021 |
|
| 5 |
2020 |
|
| 6 |
2019 |
|
| 7 |
2018 |
4.29 |
| 8 |
2017 |
3.85 |
| 9 |
2016 |
3.48 |
| 10 |
2015 |
3.18 |
| 11 |
2014 |
2.92 |
| 12 |
2013 |
2.73 |
| 13 |
2012 |
2.57 |
| 14 |
2011 |
2.47 |
| 15 |
2010 |
2.41 |
| 16 |
2009 |
2.38 |
| 17 |
2008 |
2.36 |
| 18 |
2007 |
2.33 |
| 19 |
2006 |
2.31 |
| 20 |
2005 |
2.30 |
| 21 |
2004 |
2.30 |
| 22 |
2003 |
2.31 |
| 23 |
2002 |
2.30 |
| 24 |
2001 |
2.28 |
| 25 |
2000 |
2.23 |
| 26 |
1999 |
2.18 |
| 27 |
1998 |
2.11 |
| 28 |
1997 |
2.05 |
| 29 |
1996 |
1.99 |
| 30 |
1995 |
2.08 |
| 31 |
1994 |
2.59 |
| 32 |
1993 |
3.26 |
| 33 |
1992 |
3.43 |
| 34 |
1991 |
3.25 |
| 35 |
1990 |
2.91 |
| 36 |
1989 |
2.68 |
| 37 |
1988 |
2.49 |
| 38 |
1987 |
2.32 |
| 39 |
1986 |
2.16 |
| 40 |
1985 |
2.09 |
| 41 |
1984 |
2.08 |
| 42 |
1983 |
2.09 |
| 43 |
1982 |
2.15 |
| 44 |
1981 |
2.21 |
| 45 |
1980 |
2.29 |
| 46 |
1979 |
2.39 |
| 47 |
1978 |
2.53 |
| 48 |
1977 |
2.71 |
| 49 |
1976 |
2.91 |
| 50 |
1975 |
3.04 |
| 51 |
1974 |
3.09 |
| 52 |
1973 |
3.14 |
| 53 |
1972 |
3.21 |
| 54 |
1971 |
3.29 |
| 55 |
1970 |
3.33 |
| 56 |
1969 |
3.34 |
| 57 |
1968 |
3.35 |
| 58 |
1967 |
3.33 |
| 59 |
1966 |
3.30 |
| 60 |
1965 |
3.34 |
| 61 |
1964 |
3.44 |
| 62 |
1963 |
3.55 |
| 63 |
1962 |
3.66 |
| 64 |
1961 |
3.72 |
| 65 |
1960 |
3.74 |
