1998

6.4

1997

7.6

1996

6.4

2006

6.0

1993

5.5

1992

6.9

1954

8.0

1972

8.7

1974

8.6

1956

7.7

1965

6.3

1999

7.5

2005

7.7

1995

6.4

2004

7.2

2017

6.7

1995

6.5

1992

7.1

2003

5.1

2009

5.9