1966

6.1

1995

5.6

1990

6.1

2003

6.8

1996

5.8

2007

5.5

1933

6.2

1989

5.5

2013

6.5

1967

6.1

2017

6.6

2014

6.0

1980

5.9

2005

6.4

1987

5.2

1990

6.4

2013

6.7

2001

6.8

1993

6.4

2016

6.1