1975

5.7

1979

6.6

1985

4.9

1991

8.0

1974

7.3

2015

7.0

2008

7.1

2005

6.2

1995

6.2

1951

6.6

1998

4.6

2014

6.0

2014

7.3

1975

7.8

2018

6.3

1981

4.4

1960

6.5

2002

5.5

2009

6.2

1947

6.0