1979

7.0

1980

5.5

1996

5.3

2008

7.1

2005

8.2

1974

7.6

1981

7.6

1986

7.1

1997

5.7

1980

6.0

1985

6.4

1989

6.3

1990

8.0

1982

5.5

1982

2.0

1990

6.9