1995

6.7

2007

5.3

1993

6.3

1978

6.1

1983

5.7

1977

5.4

1978

5.8

1985

6.9

1992

6.7

1990

6.2

2008

4.5

1967

5.0

1947

4.1

1953

4.8

2002

5.5

1979

7.1

1982

7.7

1994

5.9