1996

6.4

1970

7.1

1964

7.1

2001

7.3

2003

5.9

2002

6.8

2005

5.3

2007

4.0

2017

6.9

1986

6.1

1988

6.3

2009

6.6

1997

6.0

2014

6.7

2007

3.0

1972

5.7

2007

4.8

1980

6.6

2017

5.0

2003

5.3