Detailed Instructions: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Q: Since 2006, $9 billion has been invested in downtown and surrounding neighborhoods; $5.2 billion of that in has come in 2013 and 2014. Construction activity, particularly rehabilitation of historic downtown buildings, has increased markedly. The number of vacant downtown buildings has dropped from nearly 50 to around 13.[when?] Among the most notable redevelopment projects are the Book Cadillac Hotel and the Fort Shelby Hotel; the David Broderick Tower; and the David Whitney Building. Meanwhile, work is underway or set to begin on the historic, vacant Wurlitzer Building and Strathmore Hotel.[citation needed]
A:
How much has been invested in Detroit since 2006?