Year	% (national estimate)
1961	25.969395335017087
1970	32.732500276456925
1981	42.785616750113796
1983	100.59994894051569
1985	44.02818353669016
1987	48.67256637168141
1989	54.938680808750405
1990	56.70846933516578
1991	55.8206106870229
1992	51.71947739900885
1993	56.49008674101611
1994	61.71155813160587
2001	73.0017761989343