Year	Percent
1970	2.63167
1971	2.8888
1972	2.60672
1973	4.28664
1974	1.9838
1975	8.37778
1976	13.89503
1977	16.42769
1978	17.45536
1979	17.44434
1980	13.41357
1981	11.64022
1982	10.89618
1983	15.03228
1984	16.01577
1985	31.52083
1986	25.36132
1987	13.37951
1988	11.42783
1989	11.40847
1990	9.92641
1991	8.53782
1992	9.09
1993	5.40932
1994	4.76379
1995	1.10651
1996	6.63431