§ 852. Imposition and rate of tax. A tax is hereby imposed on the payroll expense paid by electing employers to covered employees. For two thousand nineteen, the tax shall be equal to one and one-half percent of the payroll expense paid by electing employers to covered employees during the calendar quarter. For two thousand twenty, the tax shall be equal to three percent of the payroll expense paid by electing employers to covered employees during the calendar quarter. For two thousand twenty-one and thereafter, the tax shall be equal to five percent of the payroll expense paid by electing employers to covered employees during the calendar quarter. An electing employer shall only be subject to the tax imposed under this article on the payroll expense paid to any covered employee during the calendar year in excess of forty thousand dollars.