1992

5.8

2004

8.6

2004

8.3

2001

6.6

1999

7.4

2006

7.9

1996

5.4

1984

8.5

1987

8.4

1998

7.2

1983

7.9

2003

7.4

2012

6.7

1976

7.9

1973

7.0

1969

6.7

1984

7.8

1989

8.3

1993

6.6

2011

6.1