1975

6.4

1984

7.2

1994

5.9

1966

7.3

2012

6.0

1978

7.6

1999

5.8

1984

6.5

2010

6.6

1989

6.2

1980

6.7

1985

7.1

1960

7.5

1928

8.0

2009

5.3

2015

7.0

2002

5.3

1995

6.9

2006

5.6

2013

6.5