One of the last counties in the state without an optional half-percent sales tax seems poised to implement it. Clark County's Board of Supervisors voted 18-10 in favor of implementing the tax at a meeting this week. Clark is one of only 12 counties that don't have the optional tax; most of the others have separate stadium district taxes. State estimates predict the tax could raise an additional $1.6-million for the cash-strapped county. Under board rules, the ordinance must receive its 2nd and 3rd readings at a meeting in July. If approved next month, the tax will go into effect on January 1, 2009.