1976

3.3

1967

5.3

1999

3.2

2007

5.6

1970

3.8

1961

4.3

1976

5.6

1975

5.7

1968

5.1

1981

4.1

1979

5.3

1999

4.0

2000

3.7

2000

4.4

1977

3.8

1969

6.2

2006

1.0

1975

2.7

1974

4.8

1990

4.6