1955

7.2

7.8

1988

5.7

2010

6.6

1993

7.0

1961

6.9

2009

6.4

1967

7.7

1990

6.1

1957

8.0

2003

6.3

2011

7.5

1982

6.4

1982

7.8

2006

6.8

1928

7.9

1960

8.2

1969

6.6

1986

7.4

1950

8.0