1972

7.1

2000

7.1

2001

6.2

2003

7.8

1992

6.7

1939

7.6

2001

6.7

2002

6.6

1980

6.6

1982

6.4

1988

7.5

2001

6.8

2001

5.4

1974

7.8

1955

7.5

1955

7.5

1999

7.4

1968

7.3

1962

7.2

2014

3.5