Article: In 1997, the Bronx was designated an All America City by the National Civic League, acknowledging its comeback from the decline of the mid-century. In 2006, The New York Times reported that "construction cranes have become the borough's new visual metaphor, replacing the window decals of the 1980s in which pictures of potted plants and drawn curtains were placed in the windows of abandoned buildings." The borough has experienced substantial new building construction since 2002. Between 2002 and June 2007, 33,687 new units of housing were built or were under way and $4.8 billion has been invested in new housing. In the first six months of 2007 alone total investment in new residential development was $965 million and 5,187 residential units were scheduled to be completed. Much of the new development is springing up in formerly vacant lots across the South Bronx.

Now answer this question: How many housing units were built in the Bronx in 2002-2007?
33,687