There were 738,644 households. 25.2% were married couples living together, 12.6% had a female householder with no husband present, and 59.1% were non-families. 17.1% had children under the age of 18 living with them. 48% of all households were made up of individuals and 10.9% had someone living alone who was 65 years of age or older. The average household size was 2 and the average family size was 2.99.
Manhattan's population was spread out with 16.8% under the age of 18, 10.2% from 18 to 24, 38.3% from 25 to 44, 22.6% from 45 to 64, and 12.2% who were 65 years of age or older. The median age was 36 years. For every 100 females, there were 90.3 males. For every 100 females age 18 and over, there were 87.9 males.
Manhattan is one of the highest-income places in the United States with a population greater than 1 million. Based on IRS data for the 2004 tax year, New York County (Manhattan) had the highest average federal income tax liability per return in the country. Average tax liability was $25,875, representing 20.0% of Adjusted Gross Income.[101] As of 2002, Manhattan had the highest per capita income of any county in the country.[102]
The Manhattan ZIP Code 10021, on the Upper East Side, is home to more than 100,000 people and has a per capita income of over $90,000.[103] It is one of the largest concentrations of extreme wealth in the United States. Most Manhattan neighborhoods are not as wealthy. The median income for a household in the county was $47,030, and the median income for a family was $50,229. Males had a median income of $51,856 versus $45,712 for females. The per capita income for the county was $42,922. About 17.6% of families and 20% of the population were below the poverty line, including 31.8% of those under age 18 and 18.9% of those age 65 or over.[104]
Lower Manhattan (Manhattan south of Houston Street) is more economically diverse. It is also racially diverse like all over Manhattan and the rest of New York City. As of 2000, the population is 41% Asian , 32% non-Hispanic white, 19% Hispanic and 6% black. 43% of residents were immigrants. These figures are affected by the demographic weight of Chinatown, which accounts for 55% of the population of Lower Manhattan. While the Financial District had few non-commercial residents after the 1950s, the area has seen a significant surge in its residential population, with estimates showing over 30,000 residents living in the area as of 2005, a jump from the 15,000 to 20,000 before the September 11, 2001 attacks.[105]
Manhattan is also diverse in religion. The largest religious affiliation is the Roman Catholic Church, whose adherents constitute 564,505 persons (more than 36% of the population) and maintain 110 congregations. Jews comprise the second largest religious group, with 314,500 persons (20.5%) in 102 congregations. The next largest religious groups are Protestants, with 139,732 adherents (9.1%) and Muslims, with 37,078 (2.4%).[106]
The borough is also experiencing a baby boom. Since 2000, the number of children under age 5 living in Manhattan grew by more than 32%.[107]