1
2
3
4
5
6
7
8
9
10
11
12
1950
-6.5
-7.0
-7.1
-7.2
1951
-7.3
-7.4
-7.5
-7.6
-7.7
1952
-7.8
1953
-6.7
-6.4
-6.6
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
-6.3
1987
1988
1989
1990
-6.1
1991
-6.0
-5.7
1992
-5.6
-5.5
-5.4
-2.5
-1.7
-1.5
1993
-1.3
-1.2
-0.9
-0.8
-0.7
1994
-0.2
0
0.5
1995
0.6
0.8
1.1
1.2
1996
1.3
1.6
1.7
1997
1.8
2.1
2.2
1998
2.4
2.5
2.8
1999
2.7
2.9
3.1
2000
3.2
3.3
3.5
2001
3.6
3.8
3.9
4.0
2002
4.1
2003
4.2
4.4
4.5
2004
4.6
2005
4.7
4.9
5.3
2006
5.4
5.5
2007
5.6
5.7
5.8
2008
5.9
6.0
6.1
2009
2010
6.2
2011
2012
2013
6.3
2014
6.4
2015
6.5
2016
5.0
4.8
2017
4.3
3.7
3.4
2018
清华大学国际关系研究院
