2006

6.5

1991

5.0

2011

6.2

1990

5.9

1890

4.9

1998

5.3

2013

6.6

2002

6.7

1998

6.8

1960

7.7

1958

8.2

1972

6.4

2011

5.4

1939

7.1

1995

7.2

1979

6.7

2001

6.1

1980

7.0

2014

6.9

2016

7.0