1995

6.5

1988

7.5

1990

6.1

2000

5.8

1999

5.5

1982

5.2

2006

5.8

1999

6.7

1982

6.0

1989

7.1

1955

7.3

1991

6.5

1946

5.0

1986

5.3

2002

4.8

1991

7.3

1994

6.2

1980

5.3

2001

5.8

2004

6.8