Blue Shield of California says it will give customers in the state a $283-million credit on their insurance premiums, saying it is fulfilling a promise to return money to policyholders when its net income exceeds 2% of revenue. The action, on top of a similar $167-million credit announced in June and returned this month, was driven partly by the weak economy. The San Francisco nonprofit insurer says it has spent less than expected on claims because people have cut back on medical care. "People are really struggling to make ends meet," Blue Shield Chief Executive Bruce Bodaken said in an interview Thursday. "As people have less discretionary spending, they're deciding that maybe they will put off that hip or knee replacement until they can afford it." Individual policyholders will see their December bills credited $135 on average, while a family of four will get a $420 average credit, reducing their annual insurance costs by 4.5%. Although Thursday's action affects only nearly 2 million of Blue Shield's policyholders in California, other consumers could be getting similar paybacks under President Obama's healthcare overhaul approved last year. Under the regulations, insurers must spend at least 80% of consumer premiums on medical care and not reserve that income for administrative costs or profit.