1970

5.6

1991

9.3

1995

6.5

2004

6.0

2003

7.2

1999

6.6

2007

7.2

1998

7.5

1992

6.6

2002

7.0

1988

7.1

1983

7.4

2002

7.0

2002

6.2

2001

5.9

2002

6.6

2003

5.7

1996

5.4

2016

6.1

1988

5.0