More than two-thirds of Americans have thought about their end-of-life preferences – yet fewer than a third have so-called living wills. Connecticut health care activists are hoping to help close that gap by joining in this year’s “National Healthcare Decisions Day” April 16, with a “call to action” event at the state Capitol. The national day is intended to stir people to choose a health care representative or proxy, and to make decisions about future healthcare treatment, in the event they cannot do so at the end of life. “It’s a difficult conversation – nobody wants to think about their mortality,” said Anne Elwell, a vice president of Qualidigm, the state’s Medicare consulting company, which is organizing the event. “It’s really about life planning — in the way that we think about what we want for our children or what happens to our possessions if something were to happen .