1989

5.0

1992

3.3

1984

3.9

1967

7.3

1971

6.4

1972

6.2

1993

7.4

2006

5.4

2006

6.0

2007

6.9

1992

5.3

1984

6.3

1984

7.2

2005

7.4

2001

6.8

1999

6.7

1997

6.1

2011

5.0

2017

6.2

2014

6.0