The Employment Baseline is the median statewide number of employees of an employer, including affiliates during the payroll periods including the twelfth day of the month in the last four months completed prior to the contract effective date. The median is calculated by discarding the months with the highest and lowest number of employees and averaging the number in the remaining two months. There must be at least four months of operation to use the median average, otherwise if there are three or less months of operation with employment prior to the contract effective date, average only the months with employment.