1970

5.6

1988

7.4

2003

7.2

2005

6.6

1999

6.6

2002

6.5

2007

7.2

2003

6.5

1998

7.5

1992

6.6

1983

7.4

2002

7.0

2002

6.6

2016

6.1

1988

5.0

1996

7.2

1997

6.3

1984

6.8

1994

6.7

2011

5.9