1975

4.0

2014

5.1

2003

8.3

1982

6.2

2007

5.6

2005

7.2

2001

7.5

1999

6.8

2003

7.2

2005

6.2

1991

6.5

2007

6.1

2006

6.2

1986

6.7

1999

7.1

1990

6.8

1997

6.6

1992

7.4

2004

1.0

1969

5.5