1952

6.7

1990

6.1

1966

6.6

2006

5.8

1996

5.3

1988

7.6

1924

7.1

1961

7.9

1972

6.2

1956

7.1

1993

5.0

1955

7.2

1968

6.9

1972

6.2

1985

7.0

1960

7.8

2000

5.1

1955

7.4

1991

4.7

2003

6.1