1962

7.1

1981

5.1

1986

7.2

1982

6.7

1979

6.5

2001

5.9

1999

5.1

1967

7.6

2003

5.6

2007

7.5

1991

6.1

2006

7.9

1974

7.5

1994

7.4

1992

6.9

1958

8.2

2009

6.1

1990

6.3

1993

7.2

1927

6.1