1995

7.0

2010

8.4

1984

6.7

1997

6.1

1975

6.1

1976

6.5

1991

6.9

1989

7.3

2017

5.9

2003

7.2

2007

5.2

2002

7.6

1963

8.1

1957

8.2

2001

7.9

2016

7.7

1970

6.9

1968

6.7

1973

6.0

1986

5.1