What are 3 reasons why health insurance costs so much?

I want to see what reasons people attribute to high high health insurance costs. Be specific and include links to your facts if possible.
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1. Ridiculous malpractice suits leading to higher cost of operation for doctors and hospitals in the form of malpractice insurance. 2. Large portion of non-paying customers (many illegal aliens) visiting hospital emergency rooms and receiving treatment. Hospitals have to pass that cost on to recoup losses. 3. The HMO and PPO systems have higher overhead due to being a middle-man between doctors and patients.
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