1
2
3
4
5
6
7
8
9
10
11
12
1950
-6.0
-6.4
-6.7
1951
1952
1953
-6.1
1954
-6.2
-5.8
-4.9
-4.6
1955
1956
-4.7
1957
1958
1959
1960
1961
1962
1963
-4.0
-3.9
1964
-1.5
-1.4
1965
-1.3
-1.1
1966
-1.0
1967
-1.2
1968
1969
1970
1971
1972
1973
-0.2
1974
-0.1
1975
0.0
0.1
1976
1977
0.2
1978
0.4
0.5
0.6
0.9
1979
1.5
1980
1.9
1981
1.8
1982
1983
2.0
1984
2.3
1985
2.4
1986
2.5
2.7
1987
2.8
3.0
1988
1989
1.3
1.2
1990
1.0
1991
1.4
1992
0.7
1993
1994
1995
1996
2.1
1997
2.6
2.9
3.7
3.8
1998
3.9
4.2
1999
4.5
2000
4.6
4.7
2001
2002
4.8
2003
4.9
5.0
5.1
5.2
2004
5.7
5.8
5.9
6.1
2005
6.3
6.4
2006
6.5
6.6
2007
6.7
2008
5.6
2009
2010
2011
6.0
2012
2013
2014