1984

7.7

1994

6.2

1988

7.8

1987

7.3

1989

7.0

1992

6.7

1998

6.6

1983

6.1

1990

7.3

1991

8.1

2003

6.2

1989

5.3

1989

6.6

1990

6.0

1993

6.5

1991

6.2

1984

6.1

1994

5.2

1996

5.4

2005

4.3