1968

6.8

1990

6.1

2019

6.7

1952

7.7

1997

6.4

1989

5.5

1988

5.7

2007

7.5

1995

6.2

1998

6.0

2012

7.3

1987

6.3

1971

6.4

1985

6.2

2015

7.6

2003

7.1

1955

7.2

1953

7.3

1962

7.8

1972

6.3