1975

7.3

1986

6.4

1989

6.2

2004

6.1

2011

6.0

2005

6.4

1997

4.8

1963

7.5

1998

4.8

1978

6.3

2004

4.9

2008

1.0

1973

7.1

2005

6.2

2016

6.7

2003

5.8

1978

6.6

1948

7.5

1968

4.2

2016

6.5