1990

6.2

1992

6.2

2015

6.0

2001

7.8

1991

7.2

1999

7.1

2006

7.0

2008

6.6

2009

6.3

1995

6.2

1967

5.7

1978

7.2

1946

7.6

1984

7.1

1990

6.5

1987

7.3

1989

7.0

1992

6.7

1998

6.6

1977

7.4