In Bauer-Schweitzer Malting Co. v. City and County of San Francisco (1973) 8 Cal.3d 942, the Assessor of the City and County of San Francisco had over a period of several years applied a 50 percent ratio in the assessment of business inventories except as to a small percentage of firms, including plaintiff, for which a lesser ratio was used. Pursuant to a writ of mandate in a taxpayer's action, the assessor rendered escaped assessments against plaintiff on March 28, 1967, for the years 1964, 1965 and 1966 and entered escaped assessments on the 1966 tax roll. During the years in which plaintiff's inventories were underassessed, section 401 required assessment of all property at "full cash value." In 1966, the Legislature amended section 401 by providing for an assessment ratio of less than full cash value for lien dates from and after the fiscal year 1967-1968. (Stats. 1966, First Ex. Sess., ch. 147, 34, p. 658, eff. Oct. 6, 1966.) The court held that the 1966 amendment to section 401 was inapplicable, stating: "But the escaped assessments here involved pertain to the years 1964, 1965, 1966, as a result of which section 401, as it was in effect during such years, applies." (8 Cal.3d 942, 946.)