1971

8.2

1984

7.7

1987

3.2

2002

6.6

2004

6.4

2005

6.7

1970

6.1

1971

6.4

1972

6.2

1973

5.7

1966

7.1

2001

6.2

1960

7.3

1980

6.3

2006

6.8

2012

2.0

2003

6.2

1998

7.3

1975

6.3

1974

5.9