1997

7.4

1977

7.2

2002

7.9

1987

8.4

1993

7.4

1992

6.5

1966

6.4

2000

7.9

1992

7.1

2006

5.3

2002

7.2

2004

7.9

1990

7.1

1984

6.4

1993

5.9

1983

6.8

2002

6.5

1987

7.6

1999

6.6

1980

7.3