1999

5.6

2008

5.8

1961

7.8

2009

4.7

2008

4.5

1990

6.1

1969

7.1

1977

5.9

1970

6.4

1981

7.3

2000

5.2

1953

7.1

2009

7.3

1991

5.4

1968

6.7

1994

6.5

1980

6.3

1996

7.3

1990

7.0

1981

6.2