1950

5.3

1964

7.0

2000

7.2

1963

6.9

2012

6.6

1988

5.7

2010

7.4

2004

5.8

2006

7.0

1994

6.6

2000

6.3

2011

9.6

1947

7.7

1990

6.1

1976

7.5

2005

6.0

1985

7.2

2002

6.4

2008

5.4

2015

6.9