1970

5.6

1991

9.3

1995

6.5

2003

7.2

2008

5.4

1999

6.6

2007

7.2

1998

7.5

2003

5.1

1992

6.6

2002

7.0

1988

7.1

1986

7.0

1983

7.4

1990

6.0

2002

6.2

2001

6.8

2002

6.6

1997

6.2

2016

6.1