How much does it cost taxpayers to sign up one ObamaCare enrollee? In President Obama's home state of Hawaii, it's $56,819.

The Obama administration gave Hawaii $205 million in grants over the past three years to set up its state-run exchange. But so far, only 3,614 Hawaiians have filled out applications — just 40% of the state's enrollment goal.

Even if Hawaii were to reach its 9,000 target, it would still cost nearly $23,000 for each enrollee.

Hawaii's low sign-up numbers have state officials scrambling to figure out what to do next year, when its exchange is supposed to rely on excise taxes charged to insurers selling through the Hawaii Health Connector.

Washington, D.C., meanwhile, received $133.6 million in federal grants to build its exchange, but so far has signed up just 5,090 — for a per-enrollee cost of $26,242.

Ironically, the city where Obama signed ObamaCare into law is just 12% toward its enrollment goal, the second worst rate in the country.

Next in line is Massachusetts, which actually had a functioning exchange website, built as part of its 2006 reform law that served as the model for ObamaCare. But the site had to be rebuilt to suit the health reform law.

After $180 million in grants, however, Massachusetts has enrolled only 8,139 in its new exchange — or $22,124 per enrollee. It had expected 250,000 people to buy an ObamaCare plan in the first year.

Of the 14 states that set up their own exchanges, just three — New York, Rhode Island, and Connecticut — have hit their enrollment targets. Eight, plus D.C., are still below 50%. Even Kentucky, which is often cited as a big ObamaCare success story, is just 22% toward its goal.

And these figures could be inflated because some states aren't reporting how many have actually paid. In Vermont, for example, 20% of those who enrolled have yet to pay their first premium. Some states have a much lower payment rate.

To be sure, enrollment numbers will climb over the next month as the March 31 deadline approaches for people who want to avoid paying the individual mandate tax penalty. That, in turn, will bring these per-enrollee numbers down.

But these states are unlikely to come anywhere near the goals set by the administration. Hawaii added just 1,420 to its rolls in January; Massachusetts gained just 3,463; D.C., 1,444.

Worse for these states, the low enrollment threatens the financial viability of their exchanges, as IBD noted last week. Exchanges in California, Minnesota, Washington State, Oregon and Hawaii face deficits and possible insolvency if they can't find ways to bring in more money. Low enrollment could also hurt the $677 million federal exchange. The administration expected nearly 4 million would enroll in ObamaCare through Healthcare.gov in the first year, with a 3.5% excise tax on insurance plans sold there helping to pay the bills.

But the federal exchange is unlikely to reach its goal — it's less than halfway there with just a month to go — so the federal government might also need additional resources if enrollment doesn't pick up.

Nationwide, 3.3 million have signed up for a plan (but not necessarily paid) through either a state or federally run exchange. That works out to $1,789 per enrollee when you count the total $5.2 billion spent on all the exchanges, the $217 million in federal grants to hire "navigators," and the $488 million the IRS spent getting ready to implement ObamaCare.