1990

5.8

2016

4.9

1989

6.5

1984

7.1

1970

6.3

2015

6.3

1988

5.2

2011

7.2

1998

6.1

1987

5.7

1984

6.8

1975

7.2

2002

5.8

2010

5.6

2016

5.9

2007

6.6

1968

7.3

2017

6.7

2019

5.9

2008

6.8