1992

6.3

1982

6.1

1997

6.4

1977

6.6

1975

6.8

2008

6.1

2017

8.5

2007

4.5

2008

5.0

1977

6.8

1976

5.6

2004

6.6

1996

6.8

1972

6.9

2004

5.9

1943

7.5

2002

6.4

2004

6.7

2006

6.2

1998

7.2