1992

6.3

1974

6.2

1973

4.8

1975

6.8

1981

6.7

1977

6.8

1972

6.7

1989

5.8

2017

6.0

1992

5.2

2004

5.9

2006

6.0

1993

6.4

2003

7.2

1971

7.2

1985

6.7

2006

7.5

2008

6.6

1994

5.7

1986

5.8