1996

6.4

1997

6.6

2005

6.3

2004

7.9

1994

7.8

2005

8.2

2006

7.5

2004

8.6

1995

7.3

2001

6.5

1979

6.7

2000

8.5

1992

5.9

1984

7.5

2003

7.6

2015

7.5

2013

6.1

1993

8.4

1973

6.9