1970

5.6

1991

9.3

1976

6.6

1995

6.5

1994

8.3

2003

7.2

1999

6.6

2007

7.2

1988

7.5

1998

7.5

1987

6.6

1992

6.6

2004

6.2

1983

7.4

2002

6.2

2006

5.5

1991

6.2

2002

6.6

2016

6.1

1988

5.0