Year	Percent
1977	0.52691
1978	0.82627
1979	0.60876
1980	0.58149
1981	0.51711
1982	0.38961
1983	0.25263
1984	3.00869
1985	0.15734
1986	0.36004
1987	0.12547
1989	0.40642
1990	0.33825
1991	0.30219
1992	0.32671
1993	0.16074
1994	0.11865
1995	0.46294