1995

6.3

1980

4.8

2001

7.5

1979

6.0

2005

6.2

2017

5.4

2004

6.3

2006

6.6

1982

6.2

2004

4.8

2008

5.3

1999

7.1

2007

5.3

1990

6.8

1997

6.6

2007

5.6

2005

7.2

1969

4.6

1986

6.7

2013

5.8