1979

7.0

1993

7.9

1980

7.1

1975

7.9

1993

6.6

1998

7.3

1979

7.0

1995

6.9

1987

6.3

2005

7.5

2005

7.8

1987

7.3

1991

7.6

1973

7.0

2000

8.1

1989

7.2

1984

8.4

2003

7.0

2005

7.0

1969

3.9