1993

4.8

2013

3.9

1977

3.4

1971

4.5

1981

3.7

1986

4.9

1991

4.6

1980

4.3

1998

2.0

1996

3.2

1999

1.0

1976

5.3

2001

1.0

2002

2.5

2002

5.5

1996

2.8

2015

5.1

1993

5.6

2003

5.6

2006

4.9