What is the test for consistent administrative construction of a statute?

23 " 'Consistent administrative construction of a statute over many years ... is entitled to great weight and will not be overturned unless clearly erroneous.' " (Robinson v. Fair Employment & Housing Com. (1992) 2 Cal.4th 226, 234, 5 Cal.Rptr.2d 782, 825 P.2d 767.) However, "[e]ven though the court will give great weight to an administrative agency's interpretation of its own regulations and the statutes under which it operates, [issues of statutory construction present] questions of law which the court must ultimately resolve." (Id. at p. 235, fn. 6, 5 Cal.Rptr.2d 782, 825 P.2d 767.)