1990

7.4

1976

5.0

1982

5.8

1967

6.6

1990

7.4

2014

7.2

1987

6.5

1972

4.0

2005

6.3

2015

6.2

1992

6.2

2017

6.8

2010

7.2

2009

7.3

1998

6.4

2011

5.5

1989

7.0

1999

7.0

2005

5.6