1991

7.1

1994

3.7

2006

4.6

1997

7.5

1998

5.5

1990

8.5

1987

6.0

1992

6.1

1988

4.6

1990

7.4

1989

6.8

1980

7.9

2015

9.0

2008

4.8

1972

8.7

1984

6.3

1999

8.7

1973

6.2

1974

6.0

1993

5.3

1985

6.9