1992

6.3

2002

6.7

1974

6.2

1973

4.8

1997

6.4

1975

6.8

2002

6.5

1981

6.7

2007

5.1

1977

6.8

1996

6.8

2004

5.9

1972

6.7

2003

6.7

2001

5.9

2003

5.7

1988

7.3

1998

7.2

1974

6.6

1989

5.8