1986

6.3

1988

6.1

1997

6.9

1985

5.2

1978

4.1

1977

5.3

1984

5.9

1993

3.4

2008

5.0

1985

7.5

1985

7.2

1990

5.6

1985

7.0

1989

3.0

1994

5.9

1991

4.7