Sometimes the most important data is the hardest to come by. In this case, I'm referring to historic sales figures from PulteGroup (PHM -0.80%), the nation's second largest homebuilder by units sold. As I noted last week with respect to D.R. Horton's sales volume, while this is the single most accurate reflection of a homebuilder's performance, not to mention the overall housing market, a comprehensive data set containing the figures is nowhere to be found.

This is why I decided to share the chart below. While researching the health of the broader economy, I dug through the quarterly filings of the largest homebuilders. In doing so, I was trying to figure out how well the housing market has recovered. And, at least from the perspective of PulteGroup, it appears that the answer is: not very well. 

Source: Quarterly filings.

There are two reasons investors should care about this. First, if you own shares of PulteGroup, it goes without saying that the more homes it sells, the higher its stock will climb. And second, because PulteGroup is a dominant player in the housing market, its success and/or failure is somewhat indicative of both that industry and the economy more generally. As my colleague Morgan Housel has previously observed, "there hasn't been a strong economy without a strong housing market in modern history."