1981

7.3

2005

6.1

2005

4.6

2003

5.5

2013

6.4

2016

5.9

1989

8.3

1968

8.1

1995

7.2

2015

7.6

2017

7.3

2014

6.1

2016

8.2

2016

7.9

1997

7.9

1994

8.5

2016

6.3

2016

6.7

1990

7.7

2016

7.0