1985

6.7

1980

6.8

1973

6.9

1982

7.1

1984

6.5

2010

7.0

1999

7.0

1960

5.0

1997

6.5

1982

4.5

1972

8.6

2009

7.3

2002

8.0

1989

8.2

1958

6.7

1984

8.1

1990

6.8

1974

7.6

1950

0.0

2014

6.6