The small town of Dunellon, Fla., tops a list of best retirement communities for real estate investing, RealtyTrac said Thursday. Six other Florida communities were on the real estate information company\'s Top 15 Retirement Hot Spots for Real Estate Investing List. The company said it identified 40 communities across the country where at least one-third of the population is 65 or older. Real estate prices have been increasing consistently in 25 of the 40, and rentals have a positive cash flow in 27. Dunellon, a community of fewer than 2,000 people in north-central Florida, was followed by Naples, Fla.; Hot Springs Village, Ark.; Douglassville, Pa.; Sun City, Ariz.; North Fort Myers, Fla.; Rancho Mirage, Calif.; Punta Gorda, Fla.; Sun City Center, Fla.; Venice, Fla.; Florence, Ore.; Green Valley, Ariz.; Seal Beach, Calif.; Orange City, Fla.; and East Hampton, N.Y. \"These popular retirement cities will very likely be an area of growth in the housing market over the next 15 years as baby boomers retire in greater numbers,\" said Daren Blomquist, vice president at RealtyTrac. \"The baby boomer generation started retiring in 2011, a trend that will continue at least through 2029, ensuring plenty of demand for both rentals and owner-occupant purchases in these markets for the foreseeable future.\"