Melbourne:

After a trend of declining population density since World War II, the city has seen increased density in the inner and western suburbs, aided in part by Victorian Government planning, such as Postcode 3000 and Melbourne 2030 which have aimed to curtail urban sprawl. According to the Australian Bureau of Statistics as of June 2013, inner city Melbourne had the highest population density with 12,400 people per km2. Surrounding inner city suburbs experienced an increase in population density between 2012 and 2013; Carlton (9,000 people per km2) and Fitzroy (7,900).

Please answer a question about this article. If the question is unanswerable, say "unanswerable". How many people did Fitzroy have per km2 between 2012 and 2013?
7,900