 In general, claim costs rose significantly over the first five years that an individual health insurance policy is in force.Several solutions were proposed for the "closed block" problem, including requiring insurers to "pre-fund" for cost increases over the lifetime of a product, providing cross-subsidies between blocks of products by pooling products across durations, providing cross-subsidies by placing limits on the allowed variation in premiums between products, or creating state-sponsored risk pools for individuals trapped in a closed block.The American Academy of Actuaries performed a study of the proposed solutions for the National Association of Insurance Commissioners and modeled the likely impact of each.