1998

6.8

2004

7.2

2004

5.7

1971

6.8

1998

7.1

2000

6.0

1971

6.5

1972

6.0

1964

7.8

1993

6.2

1994

6.2

2005

6.3

1959

8.0

2006

6.4

1984

7.7

1994

7.1

1990

7.4

2003

7.2

1999

7.4

1973

6.5