1974

5.3

1988

5.4

1997

7.2

1968

3.9

1990

5.5

2000

4.8

1993

5.2

2015

7.1

1972

6.2

1990

7.6

2017

1.4

1980

5.6

1951

4.8

1986

6.0

1999

4.4

1990

0.0

1983

6.4

2006

6.1

2023

0.0

2017

6.0