In Energy Reserves Group v. Kansas Power & Light (1983) 459 U.S. 400, 410 103 S. Ct. 697, 704, 74 L. Ed. 2d 569, the court indicated that in determining whether legislation violates the contracts clause, three factors must be considered: (1)whether the state law has, in fact, operated as a substantial impairment of a contractual relationship; (2) if the state law constitutes a substantial impairment of contract rights, does it nevertheless have a "significant and legitimate public purpose" such as "the remedying of a broad and general social or economic problem"; (3) if such a legitimate purpose is established, is "the adjustment of 'the rights and responsibilities of contracting parties . . . based upon reasonable conditions and . . . of a character appropriate to the public purpose justifying the legislation's adoption.' " ( Id. at pp. 411-412 103 S. Ct. at pp. 704-705.) The Energy Reserves court recognized that " 'as is customary in reviewing economic and social regulation, . . . courts properly defer to legislative judgment as to the necessity and reasonableness of a particular measure.' " (Id. at pp. 412-413 103 S. Ct. at p. 705.)