1997

7.0

2001

5.9

2003

7.2

1989

6.5

1994

6.2

1969

7.0

2006

7.0

1970

0.0

1993

6.4

2006

5.4

1991

5.7

1990

6.2

2003

6.5

2004

7.0

1938

1.0

2006

5.8

2002

6.5

2013

5.2

2005

6.6

2017

7.3