Detailed Instructions: This task involves creating answers to complex questions, from a given passage. Answering these questions, typically involve understanding multiple sentences. Make sure that your answer has the same type as the "answer type" mentioned in input. The provided "answer type" can be of any of the following types: "span", "date", "number". A "span" answer is a continuous phrase taken directly from the passage or question. You can directly copy-paste the text from the passage or the question for span type answers. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words. A "number" type answer can include a digit specifying an actual value. For "date" type answers, use DD MM YYYY format e.g. 11 Jan 1992. If full date is not available in the passage you can write partial date such as 1992 or Jan 1992. If you find multiple spans, please add them all as a comma separated list. Please restrict each span to five words.
Q: Passage: Daphne is a suburb of nearby Mobile, Alabama. In 2007, Daphne saw retail sales of $653,422,000 or $34,438 per capita which compares favorably to the national average of $12,364. The median household income was $62,376 against a national average of $42,934, both measured through the 20072011 period. The home ownership was 74.6% and the median home value (20072011) was $187,000. The city is part of the Daphne-Fairhope-Foley metropolitan statistical area and was named among the top 10 such areas nationwide by Site Selection Magazine. The ranking is for areas with less than 200,000 population and is based upon the number of companies either expanding or relocating to the area.
Question: How many years was the time span where the median household income was measured?
Answer type: Number
A:
4.