1984

8.1

1951

7.6

2000

7.1

2006

7.7

1996

6.6

1972

7.1

2001

6.2

1962

8.0

1992

6.7

1978

7.4

1993

7.7

1990

6.9

1998

7.4

2002

6.3

2003

7.2

2005

6.6

2005

5.8

2015

4.5

2005

7.0

2004

4.5