1967

7.4

1991

7.8

2001

5.8

2002

6.4

2007

9.0

2005

7.2

1977

6.6

2010

5.0

1976

7.1

1997

7.6

2006

7.7

2005

7.8

1996

8.5

1994

8.2

2005

7.3

1986

7.9

1966

7.4

2001

6.6

2013

6.4

1991

6.9