When the economy was booming, many hotel companies began building new properties. Some of those are opening now, resulting in a 2.5 percent increase in hotel room supply this year, just as demand is dropping by around 1 percent or more, according to Jan Freitag of Smith Travel Research. “We’re going to see a substantial decline in occupancy this year,” agreed Bjorn Hanson, an associate professor of hospitality and tourism at New York University’s Tisch Center.