1947

7.6

1987

6.5

1986

7.6

1995

8.4

1951

7.7

2001

7.8

2006

6.1

2006

6.0

2001

6.1

2005

5.4

1995

6.5

1990

6.7

1971

6.8

1954

8.0

1921

9.0

2004

7.4

2014

6.4

1968

7.3

1994

5.9

1993

7.5