The proposed increases compare with about 4 percent for families with employer-based policies.

Under the health care law, regulators are now required to review any request for a rate increase of 10 percent or more; the requests are posted on a federal Web site, healthcare.gov, along with regulators’ evaluations.

The review process not only reveals the sharp disparity in the rates themselves, it also demonstrates the striking difference between places like New York, one of the 37 states where legislatures have given regulators some authority to deny or roll back rates deemed excessive, and California, which is among the states that do not have that ability.

New York, for example, recently used its sweeping powers to hold rate increases for 2013 in the individual and small group markets to under 10 percent. California can review rate requests for technical errors but cannot deny rate increases.

The double-digit requests in some states are being made despite evidence that overall health care costs appear to have slowed in recent years, increasing in the single digits annually as many people put off treatment because of the weak economy. PricewaterhouseCoopers estimates that costs may increase just 7.5 percent next year, well below the rate increases being sought by some insurers. But the companies counter that medical costs for some policy holders are rising much faster than the average, suggesting they are in a sicker population. Federal regulators contend that premiums would be higher still without the law, which also sets limits on profits and administrative costs and provides for rebates if insurers exceed those limits.

Critics, like Dave Jones, the California insurance commissioner and one of two health plan regulators in that state, said that without a federal provision giving all regulators the ability to deny excessive rate increases, some insurance companies can raise rates as much as they did before the law was enacted.