1992

6.9

2007

6.7

2001

6.6

2003

6.1

1997

6.5

2000

5.5

2001

6.7

1999

6.1

2004

5.2

1999

6.5

1964

7.3

2012

5.7

1993

7.3

2003

6.3

2007

7.1

2006

5.4

2003

6.2

2002

6.2

2001

5.9

1988

6.2