1993

6.3

2006

7.0

1991

6.7

1984

6.0

2002

6.2

1997

6.8

2005

6.7

2007

6.5

2002

5.3

2001

7.5

2007

7.3

1966

6.7

1992

5.7

2004

6.9

1999

6.5

2001

1.3

2016

5.6

2003

5.5

1972

6.2

1985

4.5