Answer based on context:

There were 58,110 households, of which 25.8% had children under the age of 18 living with them, 40.6% were married couples living together, 9.7% had a female householder with no husband present, and 46.1% were non-families. 31.7% of all households were made up of individuals and 9.4% had someone living alone who was 65 years of age or older. The average household size was 2.27 and the average family size was 2.87. In the city, the population was 20.3% under the age of 18, 17.3% from 18 to 24, 28.5% from 25 to 44, 21.8% from 45 to 64, and 12.1% who were 65 years of age or older. The median age was 33 years. For every 100 females, there were 96.0 males. For every 100 females age 18 and over, there were 94.0 males. The median income for a household in the city was $35,850, and the median income for a family was $48,527. Males had a median income of $35,549 versus $26,721 for females. The per capita income for the city was $21,315. About 8.7% of families and 17.1% of the population were below the poverty line, including 14.8% of those under age 18 and 7.1% of those age 65 or over.

Which was the second largest group, in percentage of the households?
married couples living together