1988

8.1

2002

8.6

1986

6.1

2005

7.7

2002

6.6

1953

6.6

2000

6.5

1986

7.6

1993

7.5

1972

7.4

2006

7.4

9.0

1995

7.3

1999

7.7

1996

5.6

1979

7.3

1991

7.6

1998

6.7

1980

5.2

0.0