1989

6.2

1988

7.0

2001

7.6

1978

7.5

1999

5.6

1991

6.5

2013

4.3

2012

6.1

2012

5.8

2000

5.3

1929

6.1

1947

6.7

1997

5.1

1994

7.3

2005

7.0

2002

6.3

1982

3.9

2014

6.3

2007

6.9

1999

3.4