1991

7.4

1994

5.7

1994

7.0

1993

7.4

2003

7.2

1997

7.8

2001

6.8

1984

6.5

2006

6.6

1956

7.9

1970

7.0

2003

8.3

1987

7.6

1953

7.3

2004

6.3

1997

7.4

1998

7.3

1992

7.1

1997

6.5

1956

0.0