1991

5.3

1990

5.9

1996

6.2

2001

8.9

1992

5.7

2010

6.9

2004

7.2

2015

7.8

2011

5.0

1949

6.9

2006

10.0

2016

6.0

2019

6.5

1992

6.8

1972

7.1

1988

6.3

1982

6.4

2014

6.1

2012

7.7

2006

7.4