1970

7.1

2005

6.4

2017

6.3

1997

6.1

2009

6.6

1996

6.5

1999

3.5

2003

5.9

2007

10.0

2007

10.0

2005

5.3

1986

6.1

2002

6.8

1964

7.1

1988

6.3

1992

7.4

1982

5.7

2001

7.3

2016

7.2

2020

6.5