1934

4.1

1979

9.8

1962

6.0

1990

7.7

1966

7.1

1999

7.1

2006

5.8

1961

7.2

2001

7.3

2002

6.2

1985

6.2

1960

7.2

1975

6.9

2005

6.8

1998

7.2

2000

6.5

1999

6.7

1958

6.6

1959

6.1

2004

6.1