1981

6.6

1996

6.5

1978

4.1

1980

6.6

1983

6.4

2018

6.2

1980

5.6

2011

6.2

1985

6.9

2009

7.5

2014

6.5

1984

6.8

2013

7.3

2015

6.3

2015

3.2