1971

6.4

1989

6.8

1991

6.3

2014

7.0

2007

6.1

1986

6.9

1998

6.1

2008

5.0

1988

6.7

1992

1.0

1980

0.0

1999

5.3

1902

7.9

1999

6.3

2002

6.0

2001

5.8

1968

7.6

1962

7.9

1999

7.1

1990

7.5