From 2002–11, there has been negative net migration, with an annual negative 109 net immigrants from 2006–11. In 2009 there were 1,820 arrivals and 1,736 departures, for a positive rate of 84 immigrants. This was the first time since collecting data in 2002, there was a positive rate. Data on arrivals and departures collected by the Nauruan Customs and Immigration Office is not available, so specific immigration data is unavailable. As of the 2011 census, 57% of the population over 15 years old were legally or de facto married, 35% were never married, while 7% were either widowed, separated, or divorced. There are 1,647 households in Nauru, making an average household size of 6.0 persons per household.
Question: How much of the population over 15 years old were never married as of 2011?
Answer: 35%