1975

3.7

1990

5.7

1968

4.9

1968

5.1

1980

4.2

1988

6.1

1980

4.1

1990

5.3

1982

4.0

1979

5.3

1971

5.0

1977

5.2

1966

4.7

1970

4.8

1965

4.1

1976

5.8

1972

5.4

1991

5.0

1990

6.8

1981

5.0

1969

5.2

1973

5.0