2001

6.7

1966

2.1

1973

6.7

1959

6.5

1976

6.5

1982

8.1

1981

7.1

1985

7.1

1990

5.0

1978

5.0

2000

6.3

1958

6.2

1989

6.6

1976

6.4

1968

6.0

1999

5.4

1987

6.9

1988

7.3

1972

5.8

1980

6.2