2001

6.0

1998

6.5

1990

7.3

1987

7.6

2001

7.4

2003

7.1

1996

6.4

1982

6.6

1985

7.1

1999

7.1

1970

7.1

1988

7.9

1951

5.3

2010

6.4

1987

6.0

1984

6.1

1940

6.0

2007

3.8

1992

6.5

1989

5.7