1976

7.1

1982

7.2

1993

6.4

1992

6.7

1966

6.7

1968

7.4

1986

7.9

1987

6.0

1982

5.1

1993

5.9

2005

6.3

1966

7.4

2001

6.6

1984

6.1

1969

5.5

1997

6.8

2001

6.7

1997

5.2

1996

7.8

1965

7.3