1972

6.9

2005

6.2

2002

5.8

1980

5.7

1980

7.0

1952

7.6

1984

5.6

1953

7.2

1961

6.9

1992

7.8

2002

7.1

1976

6.4

1980

6.0

1983

4.1

2002

5.3

2007

6.7

2001

6.8

1997

8.4

1988

6.5

1994

6.8