1975

6.7

1992

6.3

1982

6.1

1997

6.4

2003

5.1

1975

6.8

2008

6.1

1965

7.1

2005

4.3

1965

6.0

1977

6.8

1972

6.1

1976

5.6

2003

7.3

1996

6.8

2004

5.9

2002

6.4

1989

5.8

1983

7.2

1987

7.1