2009

6.2

1997

4.7

2018

6.1

2015

5.1

1998

4.8

1982

5.8

2007

6.9

1968

6.9

1988

6.0

2002

6.4

2006

7.9

1981

7.0

2005

6.3

1990

7.4

1969

6.3

1989

7.0

1938

7.0

1985

5.6

2008

6.9