1971

7.5

1981

7.1

2001

6.1

2000

6.3

1985

6.2

1973

6.6

1994

4.0

1973

6.2

1987

5.7

2015

5.4

1998

6.4

1973

7.4

1972

7.4

2004

7.5

2012

6.0

1988

6.3

1973

5.5

1979

7.7

1973

6.4

1983

6.2