1972

7.5

1980

7.1

1994

7.9

1990

6.1

2009

7.2

1957

7.9

2007

7.2

1974

7.0

2009

6.8

2001

6.2

1989

7.8

1992

6.7

2011

5.6

1940

8.3

2010

7.0

2015

8.4

2009

6.0

1990

7.5

2013

4.7

1986

7.1