1986

6.8

6.4

1977

6.4

1993

4.8

2011

7.5

1985

5.9

1987

7.1

2000

5.1

1990

6.0

1998

7.1

2011

5.7

1980

6.7

1982

5.4

1966

6.2

2011

6.5

1990

6.5

2003

6.1

1976

6.0