1959

6.6

2015

7.6

1999

7.6

1990

8.5

1997

6.4

2013

6.2

2006

7.4

2017

7.5

1986

7.4

2015

7.2

1969

6.6

2012

6.8

2004

7.9

1990

6.5

1994

8.3

1990

7.7

2015

8.0

2013

7.9

2017

7.2

2001

7.7