1963

7.1

1977

6.8

1981

6.5

1987

6.5

1995

6.9

1979

4.8

2001

6.9

1990

7.4

1964

7.5

1980

4.3

1994

5.3

1985

6.2

1986

5.6

1995

5.1

1999

7.9

1988

4.5

1990

6.0

2020

7.1

1997

4.0

2002

6.4