2007

6.1

1991

6.2

1990

6.7

1993

5.5

2003

7.2

2007

6.5

2008

5.6

1974

6.6

8.0

1975

5.9

1953

7.4

1976

4.8

1989

6.4

1967

6.9

1994

5.8

1956

7.7

2002

7.1

1951

7.1

1939

6.7

2007

10.0