1996

6.4

1970

7.1

2001

7.3

2017

6.9

1986

6.1

2003

5.9

2005

5.3

1988

6.3

1964

7.1

1980

6.6

1994

7.5

2009

6.6

1997

6.0

2007

3.0

2017

5.0

2002

6.8

2007

4.0

2007

4.8

1996

6.4

2005

5.4