1972

6.4

2017

6.0

1993

6.2

1997

5.1

1986

6.4

2003

7.1

2013

6.1

2012

8.0

1993

7.3

2010

6.8

2000

6.7

2000

6.4

1947

6.7

1976

6.1

1986

7.0

2014

5.9

2005

7.4

2006

6.9

1994

7.4