1990

7.7

2006

5.8

2002

6.2

1978

5.9

1960

7.2

1970

6.0

1950

6.8

2001

6.3

1976

3.3

2006

7.8

1974

3.8

1971

6.0

1964

6.5

1990

3.5

1981

7.5

2005

5.9

2007

7.3

2004

6.9

1987

7.5

1966

5.2