Year	Percent
1972	10.99798
1973	9.3989
1974	6.00164
1975	4.80072
1976	6.59929
1977	6.39899
1978	20.69873
1979	14.61918
1980	23.89412
1981	35.19167
1982	46.2825
1983	46.15476
1984	33.90851
1985	38.12826
1986	46.93333
1987	52.08333
1988	44
1989	43.86538
1990	66.47059
1991	45.81967
1992	40