1952

5.2

2005

6.7

1998

6.9

1995

7.3

1972

6.0

1973

6.5

2002

5.7

1977

6.0

1970

6.4

2004

6.8

2002

6.5

1986

7.0

1999

6.4

2009

7.4

1993

6.3

2001

6.2

1977

6.5

1953

7.1

2008

7.0

2009

5.9