1971

6.6

1960

7.2

1973

6.3

1980

5.7

2000

7.1

2002

5.7

1970

6.5

1981

4.0

1981

7.5

2019

5.6

1994

7.0

1993

6.2

2013

5.6

1983

7.0

1995

7.9

2007

7.5

2017

8.1

1968

8.1

1994

8.7

1972

8.7