7.7

2001

6.4

2007

5.4

1952

7.0

1966

6.7

2000

7.1

1995

6.1

1987

7.4

2006

5.0

1980

5.8

1950

7.6

1979

7.2

2015

6.2

2001

7.9

1990

6.9

2015

6.7

1960

7.0

2008

6.8

2006

5.8

2011

5.5