1995

6.5

1989

7.2

1999

7.7

1998

6.7

2005

6.3

2002

8.4

1993

8.6

2006

6.9

2004

6.3

1955

7.3

1956

7.1

1957

7.1

2000

7.4

1991

7.1

1984

7.1

1993

6.2

1975

8.4

1975

7.3

2006

6.6

1994

8.5