Downtowns with highest vacancy drop, 2009-2013

Long Island downtowns are growing, albeit slowly, according to new data released by the Long Island Index on April 2, 2014. But that doesn't mean the area is booming. New development in downtowns is only inching higher, Index director Ann Golob, said, adding that Long Island landlords demand much higher rents than nearby suburban areas such as Northern New Jersey and Westchester County.

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While Long Island's vacancy rate has dropped to 5.1 percent in 2013, the Index, a project of the Long Island-based Rauch Foundation, shows there are a few downtowns that are outpacing others when it comes to filling empty spaces.

The below map shows the 12 Long Island downtowns in four categories -- small, medium, large and very large -- that have seen the biggest post-recession retail growth.