1992

7.2

1999

6.5

1988

4.7

1996

5.8

2000

6.1

1988

6.3

2007

6.5

2004

6.8

1969

5.3

1990

3.9

2001

5.7

1997

5.3

1971

5.4

1990

6.6

1998

6.3

1991

6.5

1994

6.1

1995

5.2

1970

6.7

1995

7.8

1991

6.2

1988

6.6