1934

4.1

1990

7.7

1966

7.1

1999

7.1

2006

5.8

1976

7.0

2009

6.6

2002

5.4

2001

6.4

1987

7.5

2001

7.3

2002

6.2

1997

6.8

1960

7.2

1975

6.9

2000

5.3

2002

6.1

2000

7.2

1999

6.6

2002

6.1