1984

9.2

1994

7.4

1987

7.4

1995

6.2

2006

10.0

1952

7.7

1976

7.5

2007

6.5

2003

6.5

2003

7.1

1969

6.8

1990

6.1

1986

6.7

1953

7.7

1929

6.6

1936

6.8

1981

5.8

1973

7.4

1982

5.4

1989

6.0