1975

5.3

1972

3.2

2000

5.7

2001

5.2

1968

3.6

1969

4.9

1978

5.2

2003

5.0

1981

5.6

1991

6.1

2000

4.2

2005

3.7

2015

4.6

1970

5.7

1974

1.5

1975

3.2

1995

4.4

1999

3.8

1999

5.6

1974

4.1