1970

5.6

1995

6.5

2003

7.2

2008

5.8

2007

6.5

1992

6.6

2002

7.0

1988

7.1

1983

7.4

2002

6.2

2006

5.5

1995

7.3

2002

6.6

1997

6.2

2016

6.1

1996

4.9

1997

6.3

1981

6.4

1967

7.3

1994

6.7