1973

3.0

2005

5.2

1968

6.8

2005

6.6

1969

6.7

1961

6.5

1993

5.6

1984

7.2

2004

4.3

1971

7.3

2004

7.3

1997

7.6

1981

5.4

1999

5.5

1964

7.1

1950

6.1

2017

7.4

2018

6.8

2005

5.5

1955

7.4