1996

6.4

1984

5.5

1978

4.9

1967

4.0

1974

4.8

1990

4.7

2004

6.2

1986

7.4

2002

5.7

1993

5.1

1916

0.0

1999

7.1

1987

6.8

2008

5.2

1997

6.6

1999

6.3

2002

6.0

2002

3.8

1992

4.6

1980

4.0