2009

6.1

1997

6.0

2010

5.6

2015

4.6

2011

6.2

1961

6.9

1966

6.8

1990

5.8

1986

7.0

2002

8.4

1991

5.3

1939

7.9

1944

6.9

2000

6.7

2014

5.9

2003

8.5

2015

5.7

2008

7.0

1989

6.9

1989

7.4