1984

6.4

1985

7.1

2002

6.2

2007

7.9

2007

5.8

1981

6.5

1991

6.4

1992

6.1

1995

7.3

1989

6.6

1996

5.8

1995

7.2

1937

6.7

1988

5.9

2000

6.1

1944

7.5

1995

6.5

2006

6.3

1972

7.1

1948

7.9