Here are a few interesting stats from a brief report that New York City published this month about their supply of new housing units:

• From January 1, 2010 to June 30, 2020, New York City delivered 205,994 net new housing units across the five boroughs.
• This total includes 202,956 units from new construction and 29,161 units from the alteration/conversion of existing buildings. However, it also factors units that were lost as a result of demolition (-17,400) or alteration (-8,723).
• Brooklyn saw the most supply, followed by Manhattan. The four highest-growth Community Districts were responsible for 1/3 of all new housing additions. These CDs are all formerly non-residential areas that were rezoned to allow living.
• Manhattan saw the greatest loss in housing units as a result of alterations (people combining units). This was most prevalent in wealthy neighborhoods such as the Upper East Side, Upper West Side, and Greenwich Village.

What is interesting about this last point is that it shows you that cities are far from static. New York City lost 26,123 housing units during the above time period, with 8,723 units being lost to alterations and people combining units.

The orange areas on the above map are neighborhoods which actually became less dense over the last decade. And of course, this phenomenon is not unique to New York City. We are seeing the same thing play out in some/many neighborhoods in Toronto.

What this mean is that the role of new development is really twofold. It allows a city to grow (i.e. house new New Yorkers), but it also replaces lost housing and relieves some of the pressures on the existing housing stock. I don’t think many people appreciate this dynamic — or perhaps they don’t care.

For a copy of the full report (it’s only two pages), click here.