No government agency keeps track of how your tax dollars are used to subsidize luxury apartments—job-creating neighborhood-renewers shan't be stifled. But a handy new map shows you where your investments live, and it's not in a three-bedroom Craigslist share in Bushwick.

The Municipal Art Society had to retrieve data from the Department of Finance, the Department of Housing Preservation and Development, and the Department of City Planning to make the map, which shows that 60% of the $1.1 billion in tax revenue that we forfeited last year under the 421a tax abatement went to building apartments in Manhattan that very few people can actually afford.

In Manhattan, Long Island City, and large swaths of Brooklyn, the exemption is supposed to require that developers make 20% of their units "affordable," except when lawmakers give them a loophole to ignore or dilute the requirement.

"It's not the 1970s anymore. In these booming Manhattan neighborhoods, the only value of a 421-a program is to spur affordable housing, yet the data on 421-a's affordable housing impact is largely unavailable," MAS' executive director, Margaret Newman, says in a release.

One way of measuring 421a's impact would be to look at how much affordable housing was generated under Mayor Bloomberg: In 2013, 421a helped build 150,000 new apartments; only 12,000 of them were affordable. The city loses 11,000 affordable units to deregulation each year.

Another way would be to look at some of these properties getting the exemption: a few blocks from Bloomberg's apartment, at 150 East 86th Street, developers got $5.8 million in tax exemptions over a decade to build a total of 118 apartments, only 24 of them "affordable" (and those are built off-site).

In the Financial District, 343 Broadway got $4.4 million over 20 years to build 358 apartments, only 18 of them "affordable."

On the Upper West Side, 535 West End Avenue got $3.3 million over 10 years to build 31 apartments, and just six of them are "affordable."

One57, pictured above, got $35 million in tax breaks, including for the $100 million penthouse that recently sold; for that, developers will build 66 "affordable" units in the South Bronx.

We'll have more on 421a next week.