1985

6.2

1993

5.6

1996

5.6

1994

4.9

1994

6.7

1985

5.7

1991

3.0

1989

6.6

1990

6.1

1979

6.7

1988

7.2

1982

7.1

1998

5.4

1997

7.6

1992

6.0

1986

7.2