1939

6.3

2010

6.3

2009

4.3

1964

7.0

1997

6.7

1960

7.6

1998

5.7

2013

7.7

1996

6.0

2000

6.8

1986

6.2

1975

6.1

1996

5.9

1974

6.9

1996

8.0

2003

8.1

2017

5.6

1992

7.0

1989

6.6

1996

5.4