The rate of the tax imposed by Section 3.48.010 shall be one-half of one percent of the selling price or value of the article used, as the case may be. Provided, however, that during such period as there is in effect a sales or use tax imposed by Snohomish County, the rate of tax imposed by this chapter shall be four hundred twenty-five/one thousandths of one percent. (Prior code § 4.64.020.)