1949

6.9

1986

6.4

2009

7.0

2002

7.0

1964

7.4

2009

8.5

2005

6.2

1985

6.4

2015

6.4

1991

7.5

2010

8.2

2013

5.6

2007

5.6

2016

6.3

1979

7.1

2000

7.8

2009

6.7

1960

7.7

2014

4.6