{"year":1952,"count":5.4}
{"year":1953,"count":4}
{"year":1954,"count":4.8}
{"year":1955,"count":7.1}
{"year":1956,"count":5.2}
{"year":1957,"count":3.8}
{"year":1958,"count":3.1}
{"year":1959,"count":3.5}
{"year":1960,"count":3.4}
{"year":1961,"count":3.2}
{"year":1962,"count":3.1}
{"year":1963,"count":2.1}
{"year":1964,"count":1.6}
{"year":1965,"count":1.25}
{"year":1966,"count":1.6}
{"year":1967,"count":1.1}
{"year":1968,"count":2.9}
{"year":1969,"count":1.6}
{"year":1970,"count":1.2}
{"year":1971,"count":1.3}
{"year":1972,"count":1}
{"year":1973,"count":0.8}
{"year":1974,"count":0.6}
{"year":1975,"count":0.6}
{"year":1976,"count":0.6}
{"year":1977,"count":0.9}
{"year":1978,"count":0.6}
{"year":1979,"count":0.4}
{"year":1980,"count":0.4}
{"year":1981,"count":0.3}
{"year":1982,"count":0.5}
{"year":1983,"count":0.5}
{"year":1984,"count":0.5}
{"year":1985,"count":0.6}
{"year":1986,"count":0.7}
{"year":1987,"count":0.6}
{"year":1988,"count":0.8}
{"year":1989,"count":0.4}
{"year":1990,"count":0.6}
{"year":1991,"count":0.6}
{"year":1992,"count":0.7}
{"year":1993,"count":0.6}
{"year":1994,"count":0.6}
{"year":1995,"count":0.55}
{"year":1996,"count":0.65}
{"year":1997,"count":0.6}
{"year":1998,"count":0.65}
{"year":1999,"count":0.6}
{"year":2000,"count":0.6}