1931

6.8

2006

7.6

1983

7.9

1976

7.5

1999

5.1

1996

5.8

1978

5.9

1965

6.8

2006

6.6

1990

5.8

2006

7.8

2000

6.4

1987

6.0

2013

8.2

1964

7.3

1980

6.7

1986

6.3

1990

6.2

2000

7.0

2002

6.5