Eighteen million US homes can—right now!—order up a fiber optic line that runs all the way to their door. That's 16 percent of the population, and this buildout has happened almost totally in the last seven years.

It's good news for fiber, which has been on a growth rate that exceeds anything ever achieved by copper telephone wiring and coaxial cable wiring in their first years. According to a new study of fiber-to-the-home connections (PDF), "the highest early annual growth rate for copper was 76 percent and 125 percent for coax" within its first decade, but fiber-to-the-home has already hit 250 percent year-over-year growth rates.

There are caveats. First, the huge majority of these lines are part of Verizon's FiOS buildout—and that buildout has now reached the end of its first stage. Those within reach of a FiOS connection can still order one and have it installed, but the company has no plans to pass any more homes in the near future. And no other major company looks ready to do fiber-to-the-home at that scale.

Second, less than a third of those homes that can order a fiber connection have actually done so. Verizon's take rate has been decent but not earth-shattering; on the other hand, the small non-Verizon deployments have done well, generating take rates of 52 percent.

There are more of these small projects than one might expect; according to the report, "there is actually a very long tail" of 750 other fiber-to-the-home providers.