1951

6.4

1949

7.1

1961

7.7

1967

5.5

1941

7.3

1972

7.9

1997

6.9

1989

5.1

1948

7.2

1941

7.0

2010

5.9

1999

8.0

1979

6.6

1985

6.4

1952

6.7

1986

7.6

1988

6.2

1966

6.6

1959

7.8

1990

6.8