1996

7.5

1992

6.9

1999

7.9

1978

4.0

1988

6.1

1999

6.0

1993

6.4

1998

3.7

1997

6.6

1979

6.8

2000

4.0

2003

4.1

1992

5.6

1998

6.2

2001

8.0

1989

8.3

1998

6.8

1999

2.6