In Griffith v. County of Los Angeles (1968) 267 Cal.App.2d 837, the taxpayer applied for reduction of an assessment by contending that the assessor employed an unduly high ratio in valuing the taxpayer's property under the traditional fair market value method of assessment. The court declared that the taxpayers were under an obligation to show a disparity of the ratio between that applied to the taxpayer's property and that applied to other property generally prevailing in the county. The court then stated: "To sustain his burden the taxpayer must at least make a prima facie showing in this regard. That is, he must introduce some evidence of the assessment inequality before there is any burden on the assessor. Without this prima facie showing the assessor is not obliged to go forward with any evidence. He may stand on his presumption that the assessment is fair and equitable." (267 Cal.App.2d at p. 842.)