1991

6.8

1995

7.3

2002

6.6

1991

7.3

1980

7.1

1981

7.2

2007

5.3

2006

6.6

2002

7.5

2003

6.0

2007

6.6

1997

6.2

1973

6.9

1999

7.3

1997

6.4

1989

0.0

1986

2.8

1934

6.1

2010

7.0

2009

6.0