age or older. The average household size was 2.05, and the average family size was 2.82. The age distribution was 16.5% under the age of 18, 16.3% from 18 to 24, 28.1% from 25 to 44, 24.9% from 45 to 64, and 14.2% who were 65 years of age or older. The median age was 36.4 years. For every 100 females, there were 95.8 males. For every 100 females age 18 and over, there were 94.3 males. For the period 2009–2011, the estimated median annual income for a household in the city was $59,388, and the median income for a family was $83,880. Male full-time workers had a median income of $52,221 versus $41,679 for females. The per capita income for the city was $35,644. About 10.7% of the population were below the poverty line. Culture The Newport Historic District—one of the city's three National Historic Landmark Districts—boasts one of the highest concentrations of colonial homes in the nation. Doris Duke, heir to the tobacco fortune of her father, James B. Duke, founded the Newport Restoration Foundation (NRF) in 1968, and for the next 25 years, until her death in 1993, saved much of Newport's colonial architectural heritage. Under Duke's leadership, the NRF restored more than 80 18th- and early 19th-century buildings in Newport and neighboring Middletown, Rhode Island, most of which are still owned by the Foundation. In addition to colonial architecture, the city is known for its many mansions—summer "cottages" built in varying styles copied from the royal palaces of Europe—mostly built between 1870 through 1915. The White Horse Tavern was built prior to 1673 and is one of the oldest taverns in the US. Newport is also home to the Touro Synagogue, one of the oldest Jewish houses of worship in the Western hemisphere. Newport also has the nation's oldest lending libraries, the Redwood Library and Athenaeum. The Save the Bay Exploration Center and Aquarium, located in the rotunda at Easton's Beach, welcomes 30,000 visitors and 3,500 students and teachers from across southern New England each year. Sports and recreation Because of its history as a summer playground for the wealthy, Newport has played a major role in the history and development of several sports. The League of American Wheelmen was formed in Newport in 1880. The first U.S. national tennis championships were held in 1881 on grass courts at the Newport Casino. The first U.S. Open