Year	Percent
1975	28.22229
1976	36.68385
1977	37.05995
1978	13.27019
1979	5.99308
1980	6.46673
1981	6.20678
1982	4.50859
1983	2.85446
1984	2.19761
1985	4.99873
1986	4.3659
1987	4.36846
1988	3.7632
1989	2.88988
1990	2.54142
1991	2.66641
1992	1.31924
1993	2.1292
1994	2.32383
1995	0.81137
1996	0.92963