Seventy-six percent of all U.S. adults have signed up for the FTC's Do-Not-Call registry, according to Harris Interactive, MediaBuyerPlanner reports. That's a significant increase from January 2004 when 57 percent had registered.

Many of these adults say they have either received no telemarketing calls since then (18 percent) or that they have received some calls, but far fewer than before (61 percent). Six percent of those who have registered report receiving the same number of telemarketing calls than before.

The proportion of all adults who have seen, read or heard about the registry has increased from 91 percent in September 2004 to the current 94 percent.

Sixty-three percent of those signed up for the registry do not know whether survey research firms and pollsters are allowed to call numbers that are registered. Seventy percent of those listed on the registry report that they have been called to do a poll or survey since signing up.