1991

9.3

1995

6.5

1992

6.6

2002

7.0

1988

7.1

2002

6.2

2002

6.6

1997

6.3

1994

6.7

1964

6.8

2006

7.6

2003

6.2

2006

4.3

2017

6.6

1980

6.7

1956

7.5

2002

6.4

1999

5.5

1938

7.5

1987

6.4