1975

6.7

1999

6.5

2005

7.1

1998

6.3

1996

6.8

2000

6.2

1994

3.5

2006

6.5

2005

6.6

2019

5.7

2004

6.5

1978

5.7

1993

6.2

2009

6.6

1978

6.4

2003

6.4

1989

6.2

2003

6.2

2008

6.6

2020

5.2