1983

7.2

2012

5.1

2002

6.9

1991

6.0

1980

7.1

2015

5.9

1985

7.0

2016

5.1

1994

4.5

2014

6.7

1992

4.2

2001

3.8

1998

7.4

1978

8.0

1994

8.7

2015

5.9