1998

6.6

1990

6.9

2002

6.1

2007

6.5

1997

7.1

1991

7.2

1993

10.0

2003

6.7

1997

7.2

1984

6.4

1985

5.6

1988

7.4

1973

7.6

1993

8.0

2001

6.6

2001

6.0

2001

7.6

2000

7.6

1983

8.0

2000

6.5

1999

6.8

1996

7.2

1997

6.1

1999

6.8

1995

7.0

1981

5.9