1987

5.9

1994

5.7

1989

6.3

1964

6.5

1960

7.6

1998

7.2

1992

6.1

1996

7.2

1998

7.1

2001

6.8

2002

6.2

1994

7.0

2001

6.0

1984

6.4

1985

7.1

1983

6.3

1974

7.5

2002

6.2

1998

6.2

1997

5.7